I've had no issues on 10-11 hour riding days on either of my BMW's stock seats. Don't have any complaints with my FJR stock seat, but I haven't done big numbers yet. Your seat looks excellent. How much might that set a man back? You mentioned the leaned-over position of the VFR. Are you using a bar relocation product on your FJR?
My stock seat covers lasted less than 1000 miles. They came off to be replaced by full leather comfort by Russell. This is what comfort looks like, my friends. And I expect that leather seat cover to last for as long as I have the bike with no problems.
I fully realize that seat preference is a very personal and subjective matter, but the stock 3rd Gen FJR seat had my sitz bones screaming after only a couple of hours of saddle time. With the new Russell, and the prior one that I put ~80k miles on, on the 1st Gen, I am used to being able to sit on the bike in the morning and ride all day, stopping only for gas or to take a leak.
I did that just yesterday on the new Russell, as we had an unusually warm day for November.
As for being the most comfortable stock seat ever, my 2004 Vstrom was actually a bit better than the 1st or 2nd gen FJRs were, but I put a Russell on that bike too. My old '98 VFR still has the original stock seat on it, as that works fine for the shorter rides I end up taking on that bike. I'm only good for so long in the leaned over riding position of the Viffer.