I wasn't even trying to think up an answer, but the internal coupling on our "electronics system" went on the "fritz" and I didn't get it fixed until today.
My first leica was a M3 (in 1957) and I "cut my teeth" on that one. It is very good with a 50 or a 90, but miserable with the 35mm.The lens with goggles is too big and you add several layers of glass to dim the finder.
Once I encountered the M2, it was love at first sight as they say. I put a 35/2 on it and that was that! It is one of the most "tactile" of the M's. Yes, you have to do some work, like setting the counter (big deal, you cant advance anymore when you get to the end of the roll) and just like the M3 you have to pull out that take up spool to load. An old trick was to "pre-load" several spools with film and keep them in your pocket and just pull out the finished one and grab one of the ones in the pocket.
The M2 also added the benefit of the Leicavit MP, no conversion necessary (you could get it adapted to the M3 in those days too, but it required that you send the camera to Wetzlar). I am a left eye shooter and though I have tried to shoot with my right eye it does not work. The film-advance lever was forever knocking my glasses off. With the Leicavit you could keep it at your eye and keep shooting.
For a while I was using the original MP, two were M3 finder and one had been converted to M2 finder. It might be a highly collectible camera, but it was a rough one! The case hardened gears felt like you had sand in the gear train!
An other advantage to the M2 today is that a lot of the viewfinder parts are the same for a m6 and a M2 (and that proves the basic design of the 0.72 finder too) and you can still get it fixed at a reasonable price. Try finding a replacement m3 finder!
The M4 was a nice evolution of the M2/M3, except that I have a tendency to bend my rewind cranks and have to grind out the flange at the bottom. That angled crank is fragile. The pull up "knobbly" on a M2 or M3 will take a sustantial knock before it jams (and often you can bend it back with a screw driver or a pair of pliers).
Yes. I do have M3's and M4-P's, M6's and MP's and they are very nice cameras, but taking pictures with a M2 gives me more satistaction. When I press the relase-button, it is a mechanical action, not a "multi task" operation by a chip (be it a light meter only or the full gamut of a M7).
I have also found that i shoot faster with the M2 than with the metered M's. OK, so my exposures are most likely better with the M6 (almost boringly so), but the time it takes to either "obey" the diodes or ignore them slows me down. With the M2 it is just a set,focus,shoot in one go. Over the last 4-5 decades I have used Tri-X and I can usually judge the exposure pretty well and have it preset when I walk around.
When my last leicavit died in 1985 (no more parts available) i proceeded to design and start manufacturing my own version of it for the M4P/M6/MP and I have been doing for 20 years now. Of course, the thousands of Rapidwinders I made for the M6 etc was only a pre-amble for a small series of Rapidwinder M2's (total of 400) to satisfy my own demand and that of other M2 afficinados.
I just got back one of my M2's from service (Kindermann Canada), I bought this one used some years back. The chrome is worn through at the rewind (more than a roll a year here), the shutter speed dial has the typical "press" shooters tell tale "dents" at 1/50 (flash) and 1/250 and 1/500. The rest of the shutter speed dial flange is "mint". This is the only time i wish for a small 'memory" in a camera, where you could replay thumbnails of all the shots taken with it, before it fell into my hands. No. it was not broken or anything. It just needed some oil, a couple of curtains (the patches started to look like a social disease) and the finder looked vaguely tropical in its growth. Well, now it should be good for another decade or two!
The "long shaft" of the M2 also can save your day. Once, a long time ago while on a job, I dropped the rewind spool in a river (no spare along -Never go out without an extra spool, particularly with the M3). Desperation and the potential editorial wrath had me taping the film on to the long shaft. Worked fine and i did several rolls this way. Back at the paper i put in a new spool . How the hell could I know that all the residue glue on the tape would stick to the shaft! The service guy had to use a pair of pliers and the heat from a lighter to remove the take up spool!