While expensive, I love these tires. I put them on a super stiff cross bike I have that I want to use for credit card touring. I set them up tubeless. Imagine my surprise when the ride was uber plush, my average speed was right up there with my road bike, and they gripped and carved their way though turns.
If you look at these tires, they are really light for the size - not much different than a tubular tire. Set up tubeless they are supple and comfortable and handle well. Set up with tubes in them, they feel like they have sidewalls made of hard plastic and the ride is truck-like.
So far, I have about 700 miles on them and the center slight knobs are worn down (I'm not a light rider). So I think they will last a little bit less than other tires might. But the ride quality is worth it if that's the price I have to pay for what I get out of these tires.
I think Schwalbe has done some good work here. They seem to hold up and I haven't had any punctures despite riding over some nasty stuff. I'm happy to recommend these, but set them up tubeless.
3-Star Disclaimer I attempted to run these on a winter commuter (adventure) bike. They are NOT suited for commuting on the terribly maintained shoulders in the Portland metro area. In 800 miles I had 9 flats, both tires have several significant cuts (two that require a boot), and the tread on the rear tire is already squaring off. I would have some doubts about these as gravel tires seeing as how poorly they fared, but it could just be that they don't get along with glass at all. And that I've had a run of really bad luck too.
They are very comfortable, grippy and predictable (wet and dry), surprisingly lightweight, and roll fast. I think if you just want a fast comfy tire that you could take on trailsunpaved roads they'd be pretty dang good. But if you're looking for something tough and long-lasting, I'd look elsewhere.