You certainly see more of them at matches than anything else, if that tells you anything. A lot of that is they are fairly light cans, and have a good rated recoil reduction. I would hesitate to say they're "the best", because it's subjective. Many people think Elite Iron is "the best", because they're tougher (but heavier). It's safe to say Thunderbeast makes a good suppressor that will probably hang with any other high end can.
I run a .30 cal ULTRA 9DT, but I don't see many of them. Most people run the 7" version, because it's easier to maneuver through barricades and tight places.
I chose the 9" not just for matches in 6mm, but to also run on my .300WM, which I think benefits in both sound mitigation and recoil mitigation from the additional 3", but it really pretty minor and I could have gone either way.