I've owned, reloaded for and hunted with both the 4" Model 29 and the 5 1/2" Redhawk. They were about equally accurate. I beat the poor old S&W silly with heavy loads, to the point that it had to be rebuilt once and was getting loose again when I traded it.
The 45 Colt is my bigbore cartridge these days but if I wanted a 4" heavy D/A sixgun, I would definitely buy a Redhawk. The 4" barrel is no handicap at all.