Mainly due to accidents and bargains, I have 2, a 56/50 and a .45 S&W. While I love the big .50 for hunting and the occasional GAF match, the .45 gets far more work at my local SASS matchs. The 50 goes thru powder and lead at a prodigious rate when combat shooting. The .45 is far better suited for smokeless powder as well, if you desire that. I use BP in everything, but thats just me.
Unless you're looking down the barrel, you can't tell the difference, so it really is simply up to you and your personal preferences.