For concealed carry, personal defense and as a duty weapon, I prefer a semi-auto.
While revolvers may have once been more reliable that semi-autos, that has changed. A properly oiled BERETTA, GLOCK, SIG, SPRINGFIELD ARMORY XD or WALTHER P-99 is just as reliable as a revolver, in my experience. I have shot both and actually like wheel-guns more, when I go to the range. I would also go with a revolver as a hunting weapon, if I hunted.
My first issued duty gun was a 3 inch barreled, S&W model 13. They were handy guns to carry and concealed well, but in my academy class, with had problems with them that required some to be replaced.
Later on, my agency wanted to get rid of them fast (I think we gave them to the U.S. Marshall's), after at least one suffered a forcing cone crack with .357 ammo.
I have found since then, that the sem-autoes I have carried on and off duty were just as reliable as revolvers and depending on the caliber or brand, just as likely to have problems.
Jim