The street K I encounter in the festival scene is everywhere, but it is always pretty heavily cut. You have to do a big ass line to get dissociated. Whereas pure K, even a pretty small line can get you pretty dissociated. Every once in a while, I have encountered someone at a festival with good K and on those instances, I get surprised when suddenly I become the music and have to sit down, lol.
Even pure K is inferior to MXE though. It's a middle of the road dissociative, IMO. The one thing I like better about it than the others is that it is relaxing and lasts a short time, so you can use it at the end of the night to take the edge off/get higher, and then sleep shortly afterwards. You can take K and lay down and have a little adventure which trails off into sleep, unlike MXE or pretty much any other disso besides nitrous, which all keep me up for hours.