Leicas from the early 30s had many of the fine features that gradually evolved into the IIIf. The IIIg was an intermediate step between the IIIf and M series. It's main advantage was the screw mount for older lenses. Leica was wise to drop it in favor of the M series which had a greater future. The best features of Leica have always been designs that were perfected before production began, and fine workmanship. I eventually beat my IIIf purchased new in 1953 to death. The M4 bought in 1970 is still going strong, although it shows much use.
Originally Posted by Ian Grant