Works well...
This is actually pretty much perfect. I find the strap slightly long (the excess is mildly annoying, I will cut it off sometime :) ), I'm 1750 high, so that could be an issue for some.
I've used this with my Nikon D7500 and some big lenses. The heaviest is an old version of the superb 70-200 F2.8 zoom, and it greatly reduces the load compared to the 'standard' over one shoulder straps I've used. I have walked around for a day with this combo (D7500, 70-200) on walking tracks and it didn't faze me.
While it is clearly obvious, when you're a bit tired you do need to remember the camstrap goes on before the backpack :)