A friend of mine has them. I put the plugin through the paces with some MIDI from a top-end Roland V-Drum kit. I wasn't impressed with the tracking or the sounds, maybe these would be OK for programmed drums and pop/rock but really not my bag. Kind of "big" sounding drums in a hokey way IMO, ultimately pretty fake sounding to my ears.
Some of the issues I had were probably due to the Kontakt 2 Player engine that it uses. I have been having lots of problems with Slate 3.0 b/c the Kontakt 2 Player is buggy and inefficient. I installed the SSD 3.0 WAV version the other day after reaching the end of my rope with Kontakt 2 Player, and I'm building kits in Battery 3 instead, since Native Instruments has really optimized Battery for performance.
As for performance with the V-Drums, Addictive Drums and EZDrummer completely slay everything else I've tried in terms of accurately mirroring the techniques on the drum pads (although I haven't tried SSD 3.0 yet with V-Drums.)