Hey Eric,
I am debating the same and what I heard / read so far is that the "full VF" of the 0.72 is about the same as what you'll get on the film. If you don't wear glasses it is okay. In the M7 (also 0.72) there's a 28mm frameline, really hard to see as it's all the way around the edge. If you don't mind the exact edges of your photo, you'll be good with the 0.72.
I'll do that also as I'd rather give up on absolute accuracy for the 0.72 finder. The 0.58 is very different and if you shoot 50 too, you won't like the smaller framelines.
Ben