I'm a big fan of the Pentax 645 and 645n.The n has autofocus.It's about twice the size and weight of a 35mm slr,but once you look through the viewfinder you'll be smitten-big and clear.It's designed like a 35mm slr and there's no problem with interchangeable viewfinders,it's only got the one it comes with.It's also the only MF camera that I take anywhere without my minolta lightmeter and exposures are always spot on.It's not as portable or compact as the Fuji GA line,which are great cameras,but it's really hard to beat a pentax 645 and a 45mm lens.