If by "bounce between", you mean playing Halo 3, and only putting Halo 4 in when dragged into it against my will by other people, then yes. I bounce between Halo 3 and Halo 4.
Played a decent amount of Halo 3 last weekend after not having had a chance to play much of anything online for a while, outside of grabbing the last few exciting Spartan Ops achievements. Had an absolute blast. Almost forgot how much I enjoy that game, and how many fun maps it has. And it still sounds like Halo. I suppose Reach sounds a bit better, but contrary to what people around here usually say, I'm impressed with how well Halo 3 has held up for a game from 2007.