THink one or two of you have commented on these in other threads. I thought I'd add my experience. Used these for first time on track this month. I run 205/50 x 15's on stock rims and I drive to the track so Hoosiers are out. My previous tire experience includes both track Kumhos and Michelin Sport Pilot Cups. I loved the Michelins and would never have switched if they hadn't stopped making the small size I run.
But the BFGs are as good. They stick very well and come loose in a very controlled way. I managed to drop a 1/2 second from my track best this time, which suggests they are at least as good as the Michelins. Someone here thought that there might be some tech transfer from Michelin to BFG now that Michelin owns them. Sure felt like it.
As I understand it, some have liked previous BFG track tires and some haven't. My take is that these are seriously good tires for the casual track use I give them.
Take a look at Tommy Kendall's video review on the tire rack site for more insight. And do read the BFG note on heat cycling and wear. In a nutshell, heat cycling on first use is very important, you must wait at least 24 hours after first use before using again, and the number of heat cycles you subject your tires to is irrelevant. Yes, irrelevant.