I think I'd have to say that I prefer belt these days. I prefered shafts when I started because they were a little more bulletproof but as I've gotten better and as I've started using better motors I've found that belt drives tend to put the power down smoother and the lack of torque steer is nice too. My main 2 drifters these are the TA03F and this TA05MS both belt drive:
When I'm just drifting out in the street I tend to go with my MR4TC SD because there's little rocks everywhere and they dont get on with belts

In the past I always used my TT01 but you might have seen the pics further up the page of the conversion I did to it so now I'm not too keen to scratch up the nice CF hehe.