Just my two cents,
I built a .50 several years back. Left metal in the white and aged it with bleach. It looks better the more I shoot it.
I don't get the .54 preference. Honesty, unless you are hunting grizzly, I don't see the advantage. As for accuracy, I can't imagine anything more accurate then my .50. In fact I shoot better with my fifty offhanded, then with any other rifle I have ever shot. The extra barrel weight really helps steady my hold. My average offhanded group at 100 yards is plate sized (although I have shot an offhanded 4" group at that distance), but at 50 yards I'm down to several inches or less. I don't shoot from rests, but I'm certain if I did, I could get moa or darned close to it. Yesterday I was at the range shooting at 50 yards. When the range officer saw my target his response was, "I wish I could do that with my M1A." My only suggestion is buy the caliber you are more likely to shoot in a pistol should you buy one in the future. Nuff said?