Looks like I'll be the contrarian on this one.
Several years ago, I bought a IIIc with a 35mm Summaron, 50mm Elmar, and 135mm Elmar. Even though I appreciated the quality of it, and really made an effort to like it, there was just too much I disliked. Among those was needing an external finder with anything other than a 50mm, needing to trim the leader to load it, and the separate viewfinder and rangefinder. I kept it a while, but finally sold it.
About a year ago, a friend convinced me that I should give Leicas another chance, so I kind of went all in and bought an M3, a dual range Summicron, a "goggled" 35mm f/2.8 Summaron, a 90mm Collapsible Elmar, and a few other assorted cheap lenses. For probably the first month, I couldn't put it down-it was the only camera I wanted to use. A little later on I bought an M2, which I find I actually like a little better(the 50mm framelines are easier to see for someone who wears glasses, which I do).
It's such a step forward and seems like so much less of a chore to use than my IIIc ever was. The viewfinder/rangefinder with different framelines is such a nice step forward. All of the operation and handling of the camera is more like a modern camera since you have all the speeds on one dial and don't have to worry about changing the speed without the shutter cocked(or keeping your fingers away from the spinning dial). The film just loads-yes it's a LITTLE more fiddly than a swing back SLR, but not too bad and I think actually a bit easier than something like a Nikon F(at least the bottom plate will fit in my pocket if I'm trying to load without somewhere good to set it down).
I don't see myself getting out of M mount any time soon. I also wouldn't rule out getting another Barnack some day, especially since I've picked up some nice LTM lenses, but it's not a top priority. I do have a Canon 7 to use my LTMs without an adapter(epsecially since the only LTM-M adapter I have only brings up the 50mm lines).