Klaus, for this I have to disagree with you. Reliability is the first consideration for any weapon. If it doesn't work, what good is it?
The bad guys don't care about your comfort...
For CCW, it IS a good idea to pick one that you don't mind having attached to your body all day. Comfort is certainly a factor here. This is what drives the current proliferation of small pistols in big calibers...
Mine is a 1911. It works, it hits, and I can (have) run it in my sleep. Keep in mind that handguns in general aren't all that powerful. The pundits claim that 70% of folks shot with them live.
Find something that works for you. Buy a quality holster.