Ok, I have more info on mine. Basically, I can confirm most everything said thus far. in particular:
1. The fueling curve is pretty aggressive at the low end. enough to hit the turbo pretty hard, give you a good puff of smoke, beak tires loose, attract attention, slip the clutch. lots of fun.
2. cruising with the VA box on is rock solid. you thought the stock truck had a good cruise control. The VA box is amazing because of the fueling curve centered about 2000 rpm where it makes its peak torque.
3. this box runs hot. duration without timing means a net retardation in timing. When I do a WOT run from 50 mph in 5th gear, I have to back out at 65 mph to stay under 1300 degrees pre turbo. My truck is at a disadvantage, though, because my air is completely stock and I live at 2700 feet. But y'all need to know that the disadvantage of this box is EGTs. dems the facts.
4. stacking the VA duration box with a simple pressure box is a very good thing. set the VA to its level 1 setting . now stack with EZ, Quadzilla, Bullydog, or VA pressure box -- on a lower setting. You get a much flatter torque curve (easier on turbo, clutch, drivetrain, lower EGTs, and (approximately) just as much area under the curve, and smoother acceleration. I'm running my VA box with the Quadzilla towing module (in cab adjustable 0-50-100) on the 50HP setting and loving it. The low end fueling is great -- I get light smoke, enough to spool the turbo up nicely without hitting it too hard, and the truck pulls very nicely well past 2,000 RPM to 3000 with smoother acceleration and lower EGTs than with just the duration box.
I do very much like the responsiveness of the VA duration box. Its just that you won't be able to use all of its power without a clutch upgrade and more air. turning it down and adding a little pressure is looking very nice. smooth acceleration is easier on U joints and differentials too.