No preference, had great luck with good and bad paint.
I've had this barrel for about 6 months and i gotta say, i love it. I use it on my WGP Prostock pump and the accuracy is amazing. I can't compete with my buddies flatline, but i come pretty damn close. As far as the paint that i've used in it, wal-mart crap to Draxxus. This barrel has done me proud. I've broke the same amount no matter what kinda paint i'm running.
The only con that i can come up with, is the price and the inserts. The only reason i say inserts, is because most people don't have them when they buy this barrel. Lucky for me, i just sold my freak front and back right before i picked up this baby. So, i already had the inserts. Overall, great barrel. Best barrel with inserts that i've ever used.
Great barrel, reasonable price, everyone must own one.