Hi, S-T! I think Mr. Steele pretty well covered why I think the Uberti "mainspring" is a little wierd; seems mainly cosmetic and or/redundant.
However, it wouldn't stop me from buying one if I didn't have original Wins. They seem the best value in the "1885-relatives," and have come in some sensible calibers, too.
Can't say I'm especially predjudiced against Japanese guns, but given a choice I prefer Japanese cars and Italian guns (except I'd love to have a 1960s Lancia Appia....).
I suspect that the new steels in contemporary "1885s," whether "Winchester/Browning" or Uberti, are superior. The main place that might matter is in the use of jacketed bullets in the barrels--I guess that 2008 barrels would hold up longer than 1885-era steels. That would only matter to a gun nut/experimentor or a target competitor; I imagine no mere hunter ever shot out an original 1885 barrel, even with the hottest jacketed bullet factory loads, or handloads. The 1885 ACTION was always proof to whatever was fired in it, even from the very beginning. I suspect that was the design, not particularly dependent on the steel, since Winchester and the cartridge companies used original case-colored 1885 actions for cartridge proof for years, even in 7x57 and .30-06.
Has anyone heard of a shooter having problems with the strength of the Browning "1885 Low Wall" models in .243 or .223? I know Ken Waters (RIP) worried about them in print, but I never heard of any problems.