I missed this thread, but I have had experience with the earlier 45 Colt/45 ACP stainless Bisley, I believe a 5.5" model, around 2007 - 2009.
At that time, I was shooting a lot more 45 Colt than about anything. I had an OM 5.5" (long story) 45 Colt and a 4" Smith N-Frame in 45 Colt, both blued. The stainless ones were fairly recent and I had a line on one for a really good price. At the time, I was shooting fairly often with two friends who were also SA buffs, particularly in the Ruger flavor. One of those two guys had the new stainless convertible model and it was pretty much "all that" and more as far as 45 Colts went. I used up a couple hundred rounds in his Bisley and nearly bought one for myself. I stalled, Ruger seemed to have stopped making them for a while and they got harder to find and the prices went up.
My impression was that it was typically Ruger and typically Blackhawk - not meant as a slight, with the added benefit of being chambered for two rounds I shot a lot of. It seems a versatile gun I'd be able to use forever and the 45 Colt would have done anything I'd have asked of it. When Ruger came out with the 44 Special Flat Top, I moved my 45s and went all 44 Special, which was another favorite, and I moved the ACPs in deference to 44 Special carry guns. The smaller-framed Ruger was the game-changer in the evolution of my battery.
This Bisley is a "full-sized" gun, which was OK for me at the time, but my own OM 45 Blackhawk was lighter and handier. Still the allure of the subject revolver was the versatility. I was on the fence at the time on the Bisley grip frame and did not want to admit to myself that it was just too big for me. If it fits YOU, I think this is a marvelous gun to have. For me, I had to pick between the 45 Colt and the 44 Special and, as much as I like the 45 Colt, the 44 Special won out for the compactness and lighter weight offered in smaller frames - one of which was Charter's Bulldogs, so that's the way I leaned. I definitely didn't ditch the 45 caliber because I didn't like this particular gun - it's a great cartridge and a great SA revolver. Just didn't fit my scaled down battery and component inventory.