I tried them once, I liked the OD for the most part...KINDA fuzzy wasn't bad though, I remember it being tighter actually, which I liked alot, but not as clear as the EL34B's. BUT, since I do value my clean a little bit I took them out, I thought it made the clean very plinky sounding, cold or something like that, just didn't sound right. If it wasn't for the clarity issue(which it wasn't really that bad just the B's are clearer) and the cleans, I would've stuck with them. I had a pair drop the grid and blew out a bias resistor on a recto I had but other than that, I've always seen them in my buddies amps for pretty long times.
-Nick