I'll jump in and say that I really like my R3M. I purchased it in early 2010 with a 40/1.4 and I find it an enjoyable combo to shoot.
I purchased the single coating version of the 40/1.4 and I love it. I would opt for the single coat if I had to do it again. I really love the compact size of the lens. It's a fast lens that you can use all day and all night with silky smooth operation and it won't weigh you down at all. My only complaint with it is that the bokeh can get a bit nervous at times, but of course this is my subjective opinion. It only seems to happen for me when I shoot wide-open. It is dependent on the background and the light you are shooting in, but in absolutely no way do I think it is a deal breaker.
When I purchased my R3 the prices were significantly lower. I think I paid 560-570 for my R3, brand new, and 399 for the 40/1.4. I really like the 1:1 finder in the R3, and while I do plan to get some wider lenses(such as the 15 and 28/2) I'll have to see how I like an accessory finder. It seems that the prices have gone up. At the time I purchased I did not consider the used Leica M market, but I think that if I was to purchase today I would look into the possibility of a Leica M3 or M2 and a CLA.