The RCS has a commander length barrel and an officer length grip frame so reliability should not be a problem (Sig's website says a 4.2 inch barrel but I think they just rounded the number for some reason). Having said that, I would recommend the 239 for the reasons Constantine mentioned. You'd hate to really need the gun for defense only to forget to flip off the safety.
Jim's Rules of Carry: 1. Any gun is better than no gun. 2. A gun that is reliable is better than a gun that is not. 3. A hole in the right place is better than a hole in the wrong place. 4. A bigger hole is a better hole.