Bill in his prime blows Ackerman out of the water as an announcer, but you can tell age is catching up with Bill. Bill's a Houston sports broadcasting legend and I'll always remember his broadcasts just like I'll always remember Gene Peterson's pbp as the best. Ackerman is alright, but just comes off as trying too hard sometimes. Peterson was a broadcaster without much of a forced shtick -- he was just damn good.
Heck, I just addressed this in Clutch's thread about Bill and Craig that got bumped. I like Craig a lot, but I prefer Bill, even if he's "lost a step" with age, and I think Bill has a few more years left in him. The passion for the Rockets has never left, even if working with Clyde has obviously worn him down. Craig needs seasoning, as someone pointed out. I think he'll get there. Murph? He should still be sitting next to Bill doing the broadcasts.