They required me to manually disconnect from one device in order to connect to another (e.g. from laptop to phone or tablet). As far as first world problems go, it was a huge pain in the arse. And nobody cared to mention it in their reviews (found out later in forums it was just not supported).
I ended up preferring the AirPods Pro (and the slightly worse nc, but much lighter and automatically connecting) over them, and now I hardly ever use them. So those were $400 down the drain.
If those AirPods Max work like I want (which, judging from the AirPods Pro, they will), that would be a solid $500 spent without the remorse and dissapointment, which is much better than my Sony purchase...