I've just purchased the kr-808d-1, manufacturer date, 4-12-2009. This is one amazing e-cig. A good 6-7 seconds before cutoff. Lots of vapor and a very nice throat hit...and throat hits are very important to me! The carts last a good day for me, and I was a 1 to 1.5 pack a day smoker. The battery (the shorter one) lasts me 4-5 hours per charge. Do not confuse this model with the 2 piece designs that you can buy from Red Dragon or Green Smoke....as I have tried those. I'd say this KR is the same thing as the Vapor King or Nubula which other vendors are selling. When I get my Vapor King I'll be able to confirm that.
So after spending more money than I care to reveal, my 2 main e-cigs are the 501 with manual battery and the kr-808d-1. I use the 501 a lot at home because I have the time to reload juice when needed, and the KR goes with me when I'm out and about. I'll take an extra battery with me (and an extra cart just in case) and I'm good to go for the day. I am also reloading the KR with juice. I just drip it into the hole on the battery side of the cartridge. Very easy! I don't seem to get quite as much vapor as a stock cartridge, but it tastes better and I'm still getting a good throat it.