ATE Super Blue/Gold.it's worked great for me so far.i can't see any reason to pay big money for the other fluids when this works really well(it's $25 for the 1 liter bottle at SCC,but i normally buy it at CDOC at VIR for $13 a bottle.i just forgot to buy a bottle last time i was there).with the ATE fluid and Carbotech pads i've never had any issues at all,even in 100 degree weather during 40 minute lapping sessions.
Chris