My favorite is my Les Baer Thunder Ranch Special, a very basic, but very, very well-built 1911. Why? There are many reasons, some large, some small. My first handgun was an off-brand 1911, in 1982 or 1983, and I have owned many, so the 1911 manual-of-arms is quite familiar. The 1911, with a flat MSH, is a natural "pointer" in my hands. I can detail-strip a 1911 without referring to a manual, which is a comfort to me.
The recoil characteristics of a full-sized, all-steel 1911, firing the gentler-accelerating .45 ACP, are kinder and gentler to my aging, aching wrist than my snappy .40 P229 duty pistol. My Baer has functioned 100% with all ammo tried, from round one, using magazines that would make my finicky Kimbers choke. (I have sold off the Kimbers.)
Les Baer pistols, in particular, are sculpted at the junction of the trigger guard and front strap in a way that makes them fit my hand better than a standard 1911 frame. The fit and finish are quite satisfying. Life is good!
OK, regarding my least-favorite pistol, well, I have, quite simply, dis-remembered, and refuse to dwell on the negative. Plenty of firearms have been negative experiences, but I will not bother to rank them from worst to least-worst. The bad ones have been long ago sold or traded. What I have at this time are all good.