There are two advantages of a fescue green.
1) You can keep them in the same condition as fescue fairways ... not soggier or firmer or faster or slower, but a consistent playing surface from approach to green.
2) You don't have to use the same chemicals to keep them healthy. I believe this is about to become readily apparent all across the European Union.
What's the disadvantage? That it transitions to Poa annua in many circumstances? How is that different than a bentgrass green? What are the greens at The Bridge today, bent or poa annua?
The greens at The Bridge are pure bent here in year 16.
I'm not advocating any grasses and I surely understand there are $$ issues associated with keeping pure bent pure
I recently played a highly regarded course that's a few years old with pure fescue and they were the least true greens I've played in years. They were the same last time I was there.
The only other experience I have with fescue is Chambers Bay and they looked a hot mess.
I play slow greens(as slow as 4-5) all the time and I am not picky at all about speed-in fact I enjoy the challenge of sloped slower greens.
The greens in The UK/ireland are NOTHING like the very limited experience I've had with fescue greens here, and I very rarely see poor greens over there.