Both TAC and X-Terminator are good; I mostly run TAC.
H335 normally provides fine accuracy, but is dirtier-burning and far more temperature sensitive. I've shot as many as 500+ rounds of TAC ammo without cleaning the bore of one of my .223's, and accuracy was just as good at the end. In my experience the bore would have needed scrubbing at least 10 times during the same 500 rounds.
