SP101 would be my choice. I almost bought one a while back but then saw the GP100 - it's a tank and a fine shooter.

S&W may have a better trigger, but pound for pound, Ruger is better (IMO). Depends on what you wish to do with it. If you want to show it off use occasionally, S&W is it. If you want something that is dependable and can handle just about anything, SP101 (or GP100).

BTW, Ruger has MUCH better customer service.