I have two SIG P229s with .40 S&W and 357 SIG barrels. I enjoy shooting 357 SIG and would probably do so more often if it were not for ammunition expense. The ammo expense would not be an issue if you reload, and good deals for 357 SIG ammo do come up on the internet with fair regularity. If I had to rely on locally purchased 357 SIG ammo, it would be pretty grim. Selection would be extremely limited and prices quite high.
The SIG P229 shoots either .40 S&W and 357 SIG extremely well. I have heard many say they feel the recoil of 357 SIG is less than .40 S&W. I am not sure I agree. I would say they are similar, but different. Maybe a bit more muzzle rise with .40 S&W but it seems to me 357 SIG has a sharper push back into the hand. But with the P229 either is pleasant to shoot, so arguing which has more manageable recoil is really splitting hairs IMO. The 357 SIG cartridge is definitely louder, which you will probably notice when shooting indoors. And in dim light it definitely has more muzzle flash.
Since it is a high velocity cartridge, 357 SIG does shoot quite a bit flatter than .40 S&W, 9 mm Luger, or .45 ACP, which might be advantageous for shooting out past 25 yards.