I have TKC's back and front on 990. I am a dirt rider and have no problems with them on the dirt for normal things, if I was to go serious offroad I would pick a full knobbie. On the tar I probably don't push too hard but I ride with roadies including Hyabusa and have no problems keeping pace without been stupid, but I am talking about speeds of 140 - 160 km/h.
The front wears well but the back is shagged after 3000 km so I am planning a Mefo Explorer for better mileage.
In the wet I have no problems but once again I take it easy.