A few days ago, Plex announced that a completely redesigned version of its app was getting pretty close to completion, and that a beta build would be available "later this week." Well, it's later this week, and the beta version is now in in the Play Store. Awesome.
As previously noted, it's only available for PlexPass subscribers at the current time. Of course, if you pay monthly or yearly for extra Plex stuff, then you deserve some extra perks. This is one of them, so enjoy it. Unless you don't like things that look better than things that don't look good.