I dunno, pumps haven't felt as crazy as I'm not gaining as rapidly. Biggest thing I've noticed is strength gains are coming fast. Got 255 lb bench for 10 reps. Squatted 315 ass to grass yesterday with perfect form for 2 sets of 5, really good for me.
I'm also recharging between sets really well, like damn that set was hard and normally I wouldn't be able to match the reps but then I can again.