Okay, I'll jump in on this and hopefully not be too redundant to previous posts.

NWN OC: I love this one. I have a lot of sentimental attachment as it was my first computer RPG I ever played, so take that with a grain of salt. I find enough of the people you encounter in the game to be quite likeable or interesting, such a Linu, Aribeth, Grimnaw and Tomi. It does a pretty good job of offering perks for any class or alignment as well as challenges. Can it get to be a big of a slog at times? Sure. Is the story line particularly deep or original? Probably not, but it's a damn solid game and at the price you can get it for these days, it makes no sense not to buy it.

NWN SoU: I love the mood of this game and I love that it's a little more compact than the OC. Deekin is great, but I otherwise don't find myself to be too drawn to many of the personalities in this one. Managing finances is a little more challenging which is definitely a good thing. Getting loot is less gratifying when you are able to buy anything in sight.

NWN HotU: This game is freaking great. This alone is makes the cost of NWN worth it. One thing I found interesting is that despite the fact it's the sequel to SoU, it actually ties in to the OC and does so in extraordinary fashion if you play the OC first, use the same character and stay off the internet.

NWN2 OC: I love all the new things you can do with this game as far as character development. I loved a couple of the companions such as Neeshka and Qara. There are some parts of this game that are a much more monotonous slog that the NWN OC. You end up fighting so, so, so many orcs at one point, that it really bogs things down. I'm not a fan of situations where you're forced to take a henchman along. Finally, I find it to have a hint of corniness at times. That gnomish bard I can't remember his name as well as the main bad guy are prime examples of this.

NWN 2 MofB: This had one feature that took me a while to get over, but that's as much of a me problem as anything. Once I did, this game is freaking fantastic. Your henchmen are interesting. The NPCs are interesting. The story has a little bit of grit to it as well as probably does the best job of testing your moral compass of any of these games.

NWN2 SoZ: Don't expect immersion as much as a fun, light romp. Pluses are that you get to build your own party, crafting is handled particularly well imo and the overland map allows a little bit of sandbox style exploration. The biggest flaw is that the financial aspect of it seriously goes over a cliff where you rake in a ridiculous amount of gold with absolutely zero effort.

Bonus: NWN Kingmaker: This is another fun little 12-15 hour romp. Your companions are fun. The story is interesting enough given the short amount of time for development. The premise of running for office was kind of cool too.

Actually HotU isn't a continuation of the OC. It has ties to the OC, but it's intended to be played with SoU character. The best proof of that is a book that we get in the beginning of the game and some dialogues in the first chapter. The OC companions you meet in HotU don't recognize you as a hero from this campaign. So for story purpose it's best to play HotU with SoU character, preferably playing a bridge module in between. This one won the BioWare's contest: https://neverwintervault.org/project/nwn1/module/shadohaunt.

NWN1, especially its original campaign, is one of my most beloved RPGs. And there are no evident reasons why, really :)

I'm not a big fan of 3-D engines but I strangely like NWN1 visual presentation. This game does have atmosphere, I am really in love with its art, portraits, icons of classes, skills, items and such. It also has brilliant audio component, both music and sounds (voices are not so brilliant though).

For these PROs I forgive it every of its CONs, like weak plot, rather boring quests and kinda grind-like walkthrough.

That's it :))) an atmosphere we want keep living in. I particulary, as playing wood-elf rangers, loved the forests, moreover their sunlight coming through.
NWN2 could have been so great if it had followed NWN1 philosophy.

As well as I while playing Rogue, was in love with the sound of chests lock-picked :)

BTW, just a couple of days ago I began another playthrough of NWN1 Diamond with pure Cleric (a new experience for me, both in 'cleric in NWN' and 'pure cleric in D&D' departments).