I like the Officer's because I'm a skinny guy with fairly small hands. The pistol conceals well on my frame using a Milt Sparks Versa Max II. It fits my hands better than my G26 and I'm a funky kinda guy anyway.
Reliability issues are a true concern when considering a 3 1/2 " barrel 1911.
My pistol, in original condition, would fail to feed on the last or next to last round every 3rd of 4th magazine. I have no firsthand experience with the new Colt Defender so I can't comment on how well they might run.
Loss of velocity from 5" vs 3.5" barrels is not an issue to me at defensive ranges. Well placed shots at close ranges from either barrel will stop a fight and that's all it is about.
If you are a small framed person and are willing to spend some time and or bucks on getting an Officer's up and running and willing to change out the recoil spring every few hundred, instead of few thousand rounds you may well want to look into one. I like mine.