I'd have to say "currently" to any answer I give, as I have Canon (EOS and FD), Nikon (AF and manual), Minolta MD and autofocus, Pentax K both AF and manual, Olympus OM, Yashica (AF and manual), Mamiya, Fujica and several M42 mount 35mm SLRs in my collection. I trot out whatever suits my fancy that day. These things are dirt cheap now, mostly, so I end up with multiples sometimes. I have five Canon AE-1's somehow. They all work. My Yashica's have grown to 6 somehow, and not one of them is a lemon - though the FR-II needs a bit of love to return to glory.
I guess I have no primary system, so no alternate system. Excepting Canon's T-90, Fujica's AX-3, and any Pentax ME-ish camera, I haven't found fault with any brand or body.