[Joe 90]

The Minoltas seem to age about the same, and are much lighter. They are not as strong. I did break off the Minolta flash mount quite easily. Bits like that are nothing like as solid.
However, the back is a solid door, exactly the same as the R4, but no window and with a metal spring where the window foam is to keep pressure on the film can. The R5 back door has a slightly finer pattern on the film pressure plate surface. Not sure what difference that makes.