I have _heard_ from a couple of owners over at 1911Forum.com and read via product reviews that the GI pistols both in .50GI and .45 ACP are custom quality on par with others such as Les Baer and Wilson in specific. I don't think I've ever heard it compared to STI in specific but they are all in the same pond price and production quality wise. Workmanship is allegedly high as well as performance. As to reliability I don't know. Folks report such as in the article I linked having shot 100 or more rounds through a given unit with no errors, hiccups, and good accuracy. But frankly I personally expect as much and do not at all consider 100 rds. down range to be even a break in muchless a full functionality and reliability assessment for an autoloader. Revolver yes but not for an autoloader. I've not heard anything that I can recall about how their .45 conversion runs but having as much would make sense and cents if one could get past the initial investment cost.
I have read but not heard directly that these units are/have been under evaluation for use by LEO and military thanks to it's high net energy output per the cartridge and the pistols 1911 form factor being both familiar and functional.
IMHO this round would be supreme for HD in specific ,outside of a shotgun, thanks to it's high energy ratings and low muzzle velocity reducing possibility for over penetration be the point of impact human tissue or layers of drywall and wall studs.