I had a gen 1.5, with the short rail and QD Mepro. Gun was great, but traded up to a Gen 2.5 as I wanted to be able to mount my Elcan farhter to the rear than the rail allowed. Mepro was a good optic, but washout was a problem. Got a washout remover, which fixed the problem, but it was hard on batteries... every time I turned around, they were dead.
My personal advice? If I got a Gen 1 with the mepro cheap enough, I may bite. But it'd need to be pretty cheap. I'd probably hold out for a railed gen 1.5 or newer, though, as you then have optic options.