I've used a bunch of mechanical SLRs over the years, from Zeiss Ikon, Nikon, Minolta, Canon, Leica, probably a few others too, but the one I keep coming back to is the Leicaflex SL. I eventually acquired a handful of them, because I used them so much, with a whole lot of fun factor, and dumped rangefinders (after 15 years of exclusive use), because they were not used anymore. There's a lot of good SLRs out there, but I rate the Leicaflex SL tops.