I looked around for riders that used them and it fell into to catgories..
the haters (I would never... recap POS, .. dangerous, etc) the guys that have never used nor know anyone that has used them
the others.. have run them no problems, stunters (no complaints there) and a few racers that ran the race tire.. the only "real" issue I found was weight.. they are slightly heavier than a first run tire.. CONTRARY to the above postings, these are not "recaps".. a recap uses a single rubber overlay and can separate and throw a tread..
I can tell you if the tire was "dangerous" in any way, they would not be on the road.. DOT must approve tire usage before they are allowed on the road...
I am part of the "I wont use them" crowd as I have not seen them myself.. but I will not say they are a "bad" tire or a "POS" I bet they are just fine for about 80% of the riders I have met... (never do much more than occassional bursts of speed)
Someone gives me a set, I will try them out however..