Have two, one long action M5 I preordered in 2015 and an M7 Long action I bought when they came out in 2019. I personally love them and have had nothing but good experiences with them. My original M5 is probably the smoothest action I own but I’ve also run it quite a bit and it is set up with a 105/-5 cocking so it pretty much closes itself.
The newer M7 is almost as smooth but I don’t have as many cycles on that one so I’m sure it will only get smoother. It still runs phenomenally and I’ve had it chambered in a 6.5 PRC, smokeless muzzleloader, .300 Win Mag and now a .30-06. It’s done everything I could have asked it to and kept on trucking.
If it’s one of the actions on your short list than go for it, they don’t get much nicer.