The best way to determine which is to try them both and see which fits you best. When I joined the department, I determined that my old Ruger P85 was not quite what I wanted to carry on duty - I thought (from listening to all the guys (gals too) that Glock was the way to go. So - off to the gun shops I went. Well, I tried several different models, but none of them really fit me right (the 22 came closest I think) Somebody then suggested that I try a Sig. (was kinda hesitant because of my perception that Sigs were too much $$$) BUT, after trying the P226, I was sold. This gun fits my hand like it was made for me. I especially liked (and still do) the fact that the Sig trigger guard is longer than the Glock. Thus I became the proud owner of a new 226. When the time came to buy my backup weapon - I again looked to Glock and Sig (looked at the G19 because of the double stack mag vs. the 239's single) Again the Sig fit me best, and I deceided that fit and comfort are more important than capacity alone - I did put a set of Hogue grips on it to gain just a little width. As an aside, I now really dislike the feel of the Glock trigger, but this is probably just from being so used to my Sigs.
Bottom line - Get what feels best to you, and forget what everybody else says you should shoot.
DWJ