FULL DISCLAIMER: The Paul C. Buff company provided me with a Vagabond Lithium Extreme battery unit for the purposes of testing and review. However, the following review is completely unbiased; I do not praise products if they do not deserve it.
First, a bit of background: I'm back from Las Vegas Photoshop World 2014, and it was a blast! While I was out of state, I had a whole lot of lighting equipment coming, and it was like Christmas arriving back! Recently, I decided to purchase quite a decent amount of lighting equipment from broncolor. I'm incredibly impressed with it so far (a separate review on that later, maybe! :) ). One of the original dilemmas I had when I was choosing what lighting equipment I wanted to purchase was that I do a fair amount of location work with studio flash, but not nearly enough to justify a dedicated battery power back. Broncolor offers their Move 1200 ws power pack with a dedicated lithium battery, which is an awesome unit (I've played a little with it) -- but for the price, I just didn't do enough location work to justify the expense. Don't get me wrong -- I love broncolor's equipment, which is why I own a new car's worth, but that doesn't mean I can't be a tad...thrifty when it comes down to it. :P
Enter the VLX. It's a fairly new piece of kit, released approximately six months ago. At just $399.99, it was an attractive alternative to the Move power pack for me. However, the VLX makes some pretty hefty promises that I wasn't sure it could keep. Plus, I know it's standard company statements to say that "While we feel confident that the VLX™ system can be used to power various brands of flash units, we cannot make any claim for suitability with any individual products made by other manufacturers, nor can we accept any liability for any damage that might be caused to such equipment,"(from the PCB website) but that doesn't mean it didn't make me a little... apprehensive about it. Basically, if something went really wrong and the Scoro decided to play really unkindly with the VLX, I would be out a hefty penny.
In short, here's what the VLX says it'll do:
-- Cycle 640ws in 2 seconds, or 1280ws in 4.
-- 1000 to 1500 charge cycles, lasting 10+ years.
-- Give 90 full power flashes with 3200ws of flash connected.
-- The entire battery will charge in a few hours
The above specs are certainly quite impressive, and at just $399, I was a bit skeptical. The key issue wasn't that I was worried about the Buff equipment working, though. I know that the company makes high quality stuff in general; I was worried only about it playing with the Scoro. And here's why...
The Scoro is a pretty impressive bit of equipment itself. The recycle on the power pack ranges from a mind-boggling .02 seconds up to 2 seconds -- at 3200 joules/watt seconds of power. I was afraid that the power pack might try and pull too much, too fast from the VLX. While the battery is no slouch, no external power source will easily be able to keep up with that. I'm no electrician, but I know it's not necessarily a good idea to have something draw that fast from the battery.
So I called PCB and spoke with their customer service team. They said that there would be no reason the Scoro wouldn't work with the VLX, electricity wise, but that they had no tests with that configuration/setup. The company did kindly offer to send me a VLX unit to try with the Scoro packs. OK. So that made me a little more relieved, at least that they were so willing to work with me! Props to them there.
What I had thought (and the rep agreed with me) was that it would be best to switch the Scoro to its "slow charge" recycling mode. It is meant for unstable outlets and power supplies, but in this sense it helped the lithium battery by being a little less quick in trying to draw all that power.
Now, on to the good stuff...
The VLX box arrived; it was packaged quite well and the box seems very sturdy. Good stuff.
VLX's box.The box for the unit arrived. It was sturdy and packaged well.
Opening it up, the unit was encased in nice foam pads. The owners manual and standard safety information is also included.
I wasted no time in getting a small test (just for measuring actual specs - real world test next time!). I just used a small portion of my garage to set up a Scoro unit with the VLX. I was using a Broncolor Unilite 3200ws lamp head as well. On the lamp head is Broncolor's standard P70 reflector.

As suggested in the user manual, I attached the VLX towards the bottom of the stand, so as to give the stand itself more weight and also ensure that the VLX is more secure, especially in the event of a slip. A note about light stands for those of you thinking about the VLX: Light stands of the "twist lock" type like my Giottos stands are aren't quite strong enough to support even light pressure on the battery (I pushed on it slightly to make sure that it was completely secure). It's not that the stand is in any way defective, but the twist lock isn't designed to support any pressure close to it. Next time I will use the VLX slightly higher up on the stand.
The plug from the scoro fits nicely into the VLX unit on the stand, however. Nothing to complain about plugging in. It was very intuitive and easy to use.

I especially appreciated the nice and bright status lights, giving the user more information on the battery level. A caveat, however: When I did begin testing, firing the lights, the status light would often switch to yellow while charging. When the power pack was done charging or if left idle, the light would change back to green. I'm pretty confident the yellow isn't actually indicating anything about lower power level; rather, I think it might just be that the Scoro is drawing a lot of power quickly, even in slow charge mode.
VLX Status IndicatorThe VLX has nice, bright, and colorful status indicators for battery levels.
So... everything connected all right. I was satisfied. This was a good thing. But then came the real test: Will it turn on?
I flipped on the battery -- all's good (as seen above) -- and then I went to flip on the Scoro pack.
I will be entirely honest. I was pretty sure something was going to explode.
BUT it didn't! I was ecstatic. The Scoro power pack turned on just like it does on the wall electricity. Granted, it took quite a lot longer to charge up once started (About 10 seconds, versus just a couple seconds), but overall nothing to complain about on a battery source, and this is the only delay that happens (Aside from full power shooting, of course)

The above setup shows how the single lamp was configured, and just the general pack and overall configuration.
Broncolor Scoro on VLX -- Activate! :-)Broncolor Scoro is charged to full power and ready to fire!
All is going smoothly, still! Wow. I am really impressed. Like I said, I thought that something was going to explode - again, not because the PCB equipment has anything wrong with it. Far from it, in fact. But I simply felt like I had pulled the battery out of a Ferrari and replaced it with four AA's, and was about ready to shout "Golly gee willikers, I hope this works!" To my surprise and quite happily, it did charge and work fine!
The actual test was quite simple: I ran through all the power settings on the Broncolor Scoro, over the full 10 f-stop range, from 3200ws down to 3.2 ws, and measured the recycle using a stopwatch.
Here is a table of the summarized results.

I think it speaks for itself -- the VLX is a pretty powerful little unit. You can shoot with pretty darn acceptable recycle times up until 400 watt seconds, which is plenty for most everything, except *completely* overpowering the sun. But, at the point of the agonizing recycle times, you've got a subject with no retinas, anyway. :P
Up in the 5.5 - 6 (ish) power range, the VLX does the same for Scoro what the Scoro can pull from the wall's electricity, more or less, and that's nothing to scoff at. I'm quite pleased with this performance, and I will certainly be using the VLX on my shoots. It's not powerful enough to run both the 3200 and the 1600 power packs, so I'll probably be buying another if I need to go that route.
For a full run through of all the power settings in video form, see below.
A few little gripes, however,
While the VLX is a pretty awesome addition to your lighting bag, there's a few things that I am not a huge fan of; I'm hoping that these will be fixed or changed in future VLX units.
1. Turning the lock wheel on the stand clamp is like impaling your fingers with a lot of spikes. The locking mechanism for the stand clamp is in a gear/cog sort of shape. It's rubbery, but it's not exactly soft, either. When you try to tighten the clamp on your stand, you have to maneuver your fingers in a really awkward position, which makes the clamp actually pretty painful to tighten well. The locking mechanism digs into your fingers and it's easy to get it pinched between the "cog" and the edge of the underside of the unit. Watch for pinching! I wish the VLX had a locking mechanism similar to that of an actual light stand, that I could tighten on the outside of the unit, instead of on the inside of everything.
2. The fan on the VLX is not exactly quiet (See the attached small video of me running through the power ranges on the Scoro). If you're on a small set, or for whatever reason it needs to be quiet, watch out. (You can hear an example on the video, approximately when I hit power level "8")
3. Because the clamp for the stand is rubbery, it won't damage your stand. However, this makes it prone to slippage, even if you've got the clamp tight. Especially when you're pulling/pushing on the top of the unit to plug your light units in, it will be annoying. Be careful you don't knock the unit off the stand. This could be alleviated with an extension cord.
The Bottom Line........
All that said, the VLX is definitely a worthwhile consideration for any photographer who needs a lot of nice strobe power on the go at a really, really good price. Consistent with the rest of the Paul C. Buff product range, you're getting a pretty solid piece of equipment at a ridiculously nice price. I'm pretty nitpicky, but there wasn't a whole lot of problems to find with the VLX. I would definitely recommend one (or two!); it seems to play nice with lots of different brands of lighting equipment. If you can put up with the little gripes you'll find, it's a solid choice. If location work isn't all you do, or you can't/don't want to afford a dedicated strobe battery pack, the VLX is very, very handy. Vagabond Lithium Extreme gets a thumbs-up from me.
(Stay tuned for a Part Two coming in the next couple of weeks, where I take the VLX out on location for some real-world shooting, and the images that follow!)