only tried both on in store setting not riding.
KTV are a tad softer in flex, have no removable liner, and the footbed has this little upward ramp at the end where the toes are that i think is kool as i imagine it would help to resist toe jamming.
The KTV boots i have been told use a different more expensive foam and that is why they are a bit more pricy than shred towns. the removable liner in shredtowns will make them easier to heat mold, but personally i think the liners are awesome out of the box. plus in my personal experience, liners will get slightly stiffer with each heat molding and i like to preserve every bit of softness.
I ride the 2012 RAD liners in the 2011 RAD shells and i really love the new liners, but have my eye on the KTV for maybe next year or later... if something better from slingshot doesnt pop up and redirect my attention haha