I used Leica M2/M3 cameras exclusively for 35 years. My first SLR was a Nikon F3, purchased used in 1999. While I appreciate the quality of Leica cameras and lenses, I have no illusions regarding its shortcomings in actual use. If the OP wants a Leica and can afford it without undue stress, it's not a bad choice, but a limited one. I think the M9, being full-frame, is more useful than the M8, and a couple of years newer, but $1500 v $3000 is a factor which cannot be ignored, particularly if the rangefinder experience doesn't work out. I've also uses a Leica IIIF extensively, with screw mount lenses. If you can abide that primitive viewfinder, a Leica M of any vintage will be paradise. I bought lenses for the M9 in addition to the lenses I used over the years, which later proved useful on a Sony A7, but I would not recommend buying any rangefinder lens for the Sony when you can buy native lenses which are superior in every way for less money.