I have one, which I think is a kr808 (it's hard to tell and the place I got it from didn't specify). It only takes cartos, and I find the flavor and vapor production so inferior to the 510 that I don't even want to waste the juice to fill a carto. I also tried the cartos for it on my 510 (with an adapter) and they still aren't very good, despite being brand new and filled properly. Who knows, maybe I just wasn't using it properly...
LOL @ the 510 autos going off! I think I'd rather push a button!