Save up a little more and buy either a Sig or a Glock.The Ruger "P" series are fine guns.If the Ruger is within your budget I would say go for it.I've never owned a S&W Sigma but have heard mixed opinions.For my carry gun I prefer my Glock M-27.It's fun to shoot and easy to conceal.There are so many choices out there.I would see if you can shoot different guns and see which one fits you needs.
Ruger Redhawk