I've got the full frame R5 and I love it. I used it for birds and everything else from the day it arrived in December 2020. I don't think I've picked up my 7Dii since the R5 arrived. But when I saw the spec and price of the R7, I needed to give it a go. The R5 gave great quality, blowing the 7Dii out of the water, but even with the 100-500 it lacked reach. I had to wait for the R7, but since it arrived in August 22, it's my bird camera almost exclusively and the full frame R5 gets used for all the other stuff. The extra reach of the crop sensor makes a world of difference, and the 32MP sensor gives more pixels per bird than the 17.5MP of the R5 in crop mode, at a third of the price.
Don't let the APSC sensor put you off if what you want is birds. It gives great quality, and it will probably beat the full frame once cropped in, as bird and wildlife images almost invariably are. Full frame is great for landscapes, people, and other stuff, but the lack of reach makes them not so great with small birds in bushes or birds in flight.
A selection of migrating eagles from September, plus a few more recent shots, all with the R7 and RF100-500. Robin, wren and waxwing with 1.4x converter added.
