I've already got an R3A (and L), so I'm not sure if I should convince myself to get this or not (although it's a very decent price).
I've tried the double-viewfinder-rangefinder thing (with 90 framelines to focus and 135 external finder to frame) and I'm not the biggest fan, seems I tend to shoot things that aren't there by the time I've moved my eyes.

One thing I've always wondered, what's the field of view like looking through the rangefinder?
I know it's not meant to be a real viewfinder, but on my R3A for instance, the rangefinder patch is about the same size as a 135mm frame. So maybe if the RF view roughly corrensponds to a 90/105/135mm view, then I'd be very tempted...