Not much to choose from between the Colt & the S&W but for me I'd surely take the S&W Bobtail Commander Sc; as for the Sig, I'd pass on it given the other 2 options.
If you want to spend a few bucks more, a Dan Wesson Guardian would be a step up from the other 3.
MM
S&W Bobtail Sc
Dan Wesson Guardian