I have three different .44 mags. A S&W custom shop rig with a scope, a Colt Anaconda, and a regular old 629. The plain old 629 shoots the best of all. However, from a bench ....the custom shop is more accurate than some production rifles at 100yards. I shoot custom loads, and have been so lucky as to fire a 1" group at 100 yards from a bench with sand bags. Otherwise, my handgun skills suck!
The ammo cost for the 44 is largely dependant on the projectile and the brand name. Get some Master loads. They are cheap and they are HOT! In fact, the same grain Master vs. Corbon....the Master jumps around more than the Corbons. If you really want some fun, get some 300 grain bullets and shoot some milk jugs full of water. The 300 grain is a wrist breaker in a smaller wheel gun.