Anyone still playing persistent worlds nowadays? Seems like the perfect fit for the trolls and deviants of the forum .
About 80% of my total playtime in NWN has been on the Ravenloft themed PW and I've been a fairly active presence on it for about 7 years or so.
On the technical side of things, it's pretty good - lots of areas and dungeons, some of them quite well designed and interesting to explore, a few of them being fairly secret and some class specific (A hidden mage refuge comes to mind). A lot of the dungeons in Barovia and Har'akir are a faithful adaption of the ones found in SSI's Ravenloft games, so I'd imagine it'd be cool for a fan of Strahd's Possession/Stone Prophet to check them out, though they are comparatively antiquated and not very interesting as PvE content compared to the newer locations. There's also a scripted weather/season system in place which influences certain spawns, mobs, loot tables and what have you. Of note is the outcast system for spellcasters/non-humans and others deemed undesirables in the settings.
In regards to the playerbase and DM side it's a mixed bag and can vary greatly - as is the case with big PWs most of the time. I myself have steered away from retarded drama and the resident weirdos and cybersexing degens (there's a sizable amount of those types even if erotic roleplay is a permaban offence according to server rules) have left me alone. DMs aren't very active and approachable as well, unless you're in an official faction, though even that is not certain to net you very frequent DM events and interactions.
Don't know much about the other servers honestly. I am ill inclined to shill about the server I play on, considering it suffers from the common faults of your average PW experience - namely weirdos gravitating towards them, but I'd recommend trying out a PW at least once. When things pick up it can be a great time - no other RPG can replicate the tabletop experience as well as NWN when you participate in an event alongside a competent DM, who can channel Aurora's capabilities. Done my fair share of crazy shit on my toons, but said moments are sandwiched between periods of prolonged relative dullness, but when the 'good' periods come it's great fun.