While I prefer the handling and reliability of a full size, there are times when it just isn't practical. At my work, I have been told that no guns are allowed. This is not in the employee handbook, but was told to me by the owner of the store. As a result, I have to be extremely cautious about what I carry. I can't get made. That means I either have to carry a BUG in a pocket holster or a larger gun in a Smary Carry holster. I don't really like either of those options, but the SC is what I do.
That means a short barrel, short butt and very light weight are critical. I carry a Springfield Micro. It took a while to find a reliabile defense round, but the 165 grain Federal Hydra-Shoks have never failed in this pistol.
On my day's off, I carry either a full size, full size Operator or a 4" Champion. The Champion only gets used if I'm wearing a shirt that requires IWB carry. Loose and untucked buttom-up shirts will easily conceal an OWB holster and the 5" barrel guns get the nod.