Since there is only 3/4" difference between those barrel lengths, there isn't much difference in how they feel and shoot. I prefer the 4 3/4" because of the appearance as much as anything.
A single action with the 7 1/2" barrel is another matter. I can shoot it with a lot more accuracy than a shorter barrel.
Handling and drawing from a holster aren't that bad with a 7 1/2" and if it's a .45 the weight isn't really an issue.
Matt Dillon's shooter had a 7 1/2" barrel and he handled it well!
I've had all the barrel lengths from sheriff's model to buntlines. The 7 1/2 shoots just about as good as a 12" buntline. I've found the 5 1/2 as the best over all. It's still fast enough on a draw and shoots almost as good as a 7 1/2. I always thought the 4 3/4 was just plain sexy. Even if the barrel has an ejector rod, it's almost useless with a barrel less than 4 3/4. The sheriff's models are cool, but a reload is quite a bit slower. But it's the ultimate pocket carry in this style pistol. 45 Colt is king, good stopping power and accuracy