I have been shooting rangefinders for a greater part of my life, got used to the limitations and the pro's of using them.
Recntly however I picked up a Canon EOS 3 in perfect condition along with a 50mm 1.4 AF, 35mm 2.0 AF and a 100mm 2,0.
Although being huge compared to Leica M4's the speed of use, the lightmetering modes, the autofocus has changed my photography in a possitive effect. It's faster, much faster in everything. It's also noisy but having taken this as a non-issue becasue it really isn't such a big thing as some people might try to explain defending their leica purchase it is on the whole a better setup looking at the end result that. Low light ... not a problem, sports, macro, super-wide to super-tele ... not a problem.... weight and size, yes it's heavy and yes it's pretty big..... and the price .... well very much cheaper than anything with a red-dot, quality wise you will not see any difference unless studied with a microscope...