I never shot the Sigpro, but when I handled it in the shop, it didn't feel as well constructed as the alloy-framed SIGs. The p229 is built like a tank, albeit a compact sized tank. I had a p226 that accidentally bounced on a concrete floor and the only scratches were on my aftermarket night sights.
That 357SIG round in the p229 or p226 is like a laser. I used to shoot unshaken (and unopened) soda cans with my p226 from 25 to 35 yards away. From the closer range, a bullet impact would cause the can to violently rupture, splashing me where I stand. The .40 S&W usually would just knock it over.