Hands down on Luck perms. Pex hasn’t been on great on sponge as it was on bukkit. and PermissionsManager is pretty easy to use with the in game GUI if you are looking for a gm replacement. But LP is my go-to suggestion and has pretty good database support, not sure if that has gotten better in PM yet.
also Nucleus is definitely the way to go if you want a full “esssentials” replacement. It’s as close to essentials as you get, with better modularization. There is also EssentialCmds but meh I wouldn’t recommend it personally.