Depends on your level of knowledge and/or desire to learn the proper handling and care of the weapon.
Ease of operation:
Semi-auto pistols often have a plethora of levers and buttons (safeties, slide releases, decocking levers, magazine releases, etc.) that you will have to be intimately familiar with if you are going to trust your life to it. You had also learn and practice the TAp-RAck-Bang drill in case of a stove pipe (failure to fully eject a spent case) or Failure to Fire (FTF).
Revolvers - Point gun, squeeze trigger, bang! In the 1 in a 1,000 chance that it does not go bang, squeeze the trigger again.
Care and feeding:
An auto loader requires more maintenance and more mechanical aptitude than does a revolver. If an automatic pistol is carried in a pocket, especially without a pocket holster, it will collect lint and debris that can cause a (FTF) at the most inconvenient time. To avoid this I recommend two things, 1. Use a holster. 2. Field strip, (entails the removal of the slide and barrel), clean and test fire any auto pistol used for concealed carry at least once a month.
Revolvers on the other hand usually operate without a hitch even when they are filthy dirty and don't require the removal of any parts for a general cleaning. However, I still recommend the use of a holster as a safety measure. This goes for ladies hand bag carry as well. Keep you piece in a separate compartment away from hair brushes, lip stick, ballpoint pens, car keys or any other objects that could get entangled in the trigger causing an Accidental Discharge (AD). Or better yet invest in one of those handbags designed specifically for CCW holders with a built in easy access holster.
Auto-pistols can be ammo sensitive, not wanting to feed some brands or types of ammo properly causing jambs and FTFs.
Though a revolver may shoot some ammo more accurately than an other I have yet to see or hear of anyone experiencing a jamb or FTF due to a particular brand or style of ammo.
Hope this helped.