So basically, you can get a .357 mag s/auto pistol that throws th ebrass all over the place and is ammo sensitive, that you can't shoot .38 Specials in or a revolver that will function with either light or heavy loads and you don't have to chase your brass.
.357 mag is a REVOLVER cartridge. You can build a pistol that it will work in but it was designed for a revolver and therefore is most efficient in a revolver platform. .45 ACP was designed for an auto pistol. You can build a revolver for it, but it works best in an auto pistol. If you want .357 mag performance in an auto pistol, go with the .357 SIG, .38 Super, or 9mm+P+. If you want .45 ACP performance in a revolver get a .45 Colt or .44 Special.
Actually, the .45 ACP revolvers work better and are more justifiable than .the .357 mag autos.