You could ust as well asked what is the best brand of whiskey, or the best truck is Ford? GM? Dodge?
For my two cents I'd suggest Pedersoli. I believe there is a sale on .54 cal now, kits available from Dixiegunworks.com
I have been a metallurgist since JKF was romping around DC & can say that Pedersoli uses hands down the best steel for their assorted gun barrels. "Best" meaning when that impossible-to-happen thing happens anyway, the barrel is like to more or less survive, meaning you get to retain your present compliment of body parts.
I've also paid some attention to antique guns since Harry had about finished "giving 'em Hell" On that score I must agree Pedersoli can be just a tad squirrelly. Fortunately with a kit you can pitch the Picasso-designed sideplate and put a real forend cap on it. You will end up iwth a metallurgically and structurally sound gun, appearance up to you.
Me, I'm not doing so much in the shop now, hands forgot what to do, some would say its the date on my driver's license. Anyway this afternoon Mr. UPS promises to deliver me a finished Pedersoli .45 "Kentucky" for target shooting. Having smallish hands I expect to rasp down the grip a bit. Given some aesthetic knowledge of American pistols I might change the sideplate & add an inlay or two. I'll try to ignore the forend cap . . . Fortunately if you look at a lot of pictures of original Kentucky pistols some of them looked pretty bad, too, so I suppose I can make this thing up to be authentic, if not beautiful. Woulda bought a kit but want to shoot NOW.