For myself, NWN 1 was my introduction to the D&D CRPGs, so a good deal of my fondness for it may lie in the nostalgia factor. I played Icewind Dale and BG quite a bit later.
The base campaign may have been quite meh (I enjoyed it for what it is, and while it lacked BG's many strong points it being 3e rather than 2e is a huge improvement all by itself. Act 2 was a bloated mess, but there are good quests and moments to be had regardless), but the expansions are most certainly worth a go. And there are numerous great modules to play, which often outshine Bioware's own work in what they offer to the player - it's too bad / all too telling that perhaps the most known one is, um, of raunchy variety (A Dance With Rogues...). It's a great, if not fully accurate (ToEE is a lot closer) 3e engine with practically infinite content to play.
NWN 2, though, didn't get as much attention and community effort thanks to how horrid its toolset is to use compared to NWN 1's (Baldur's Gate: Reloaded is really good, but it's also janky as all damnation - I am still waiting on Reloaded 2 to come out, had hoped it'd be out before BG3 releases). The campaigns are quite good though, even if the base one was really heavily cut (the Obsidian curse remaining from KotOR 2, no less). MotB is downright brilliant, and SoZ is a great sandbox with full party building and a really good dialogue system which more games should have used (only Wasteland 2 did something similar, to my memory, and not nearly as detailed), where you can hot-swap characters mid-conversation to choose skill- or race- or class- or alignment-based responses.
