Wow... I'm still perplexed about some of the observations many of you have on the VKs. I have one kit I ordered from Steve at vapor4life, and I ordered another one from Eastmall (David Yang bought the vaporello supply) These units are identical except the LED is a different color. Same exact design, long battery, 2-hole. I have 10 batteries from the E9 type unit (including 2 from Red Dragon), 6 standard e-cig E9, and 2 longer batteries for the E9 I ordered from e-cig. All the batteries from RD/E9 work better than the VK type batts.
With the VK (KR808) batteries, you have to draw in the air more rapidly to get good vapor, and they don't turn on unless you draw in at speed. The RD/E9 batteries kick right in, with a nice slow drag and seem to produce more dense vapor. I haven't experienced a short cut-off with any of my RD/E9 carts. They go about 4 seconds, maybe 5. I know battery designs change a bit over time (the manufacture can make some changes), so some of you with a 2-second cut-off may have a slightly different batch.
You really need to compare apples to apples with the batteries and carts. Most of the carts sold for the RD/E9 are crappy with a different type of core (including those from e-cig.com, Red Dragon, ePuffer, and eSmoke). If you order the Smoke51 carts, they are the same core and liquid (and least in terms of how they act and taste) with the VK type carts. (if you take them apart and examine the core material's, you'll see what I mean) Compare a smoke51 cart on a RD/E9 to a VK cart on a VK, and the RD/E9 is a much better smoke and the act and taste the same. To truly compare apples to apples, but a VK cart on a RD/E9 (they screw on, just not all the way down), and put a VK cart on a VK. The RD/E9 still wins in my book. Are you folks doing a similar comparison, or just vaping with the crappy carts that come with most RD/E9 type units?
The best combo I've still found is a VK type cart (or a smoke51 cart) on a U9 USB passthrough from e-cig.com. I have two passthroughs, one at home, one in the office (and just ordered one for the car). I vape 10+ cartridges on them each day (OK I'm a chain-vaper).
Do I just have 2 lousy kits for KR808D's? Maybe a 4-hole is better, or maybe later battery designs. Don't get me wrong, they are not bad, just not as good as the RD/E9/Bloog/etc. style in my book, as long as you have the right Carts on them.