NWN is way better. I completed Origins and had some fun with it, especially the big boss battles. I loved the engine, liked the story, characters, dialogue, voice acting, which usually I hate in games, but this one kept me mostly interested. The only thing I wasn't happy with was the combat and the character building, but they are big things... The combat wasn't terrible but it was just so basic. I hated having a healing aura that does all the healing work for you... and I hated that everyone regens to full immediately after every fight. It meant that there was no resource management at all, you just unload all your shit in every fight and are back to full for the next one. And there are no ambushes at all so you never have to fight while low on anything.
As for character building, I really like that they made their own systems instead of just AD&D, but it was again just too simple. In NWN you get a huge screen full of spells to choose from every level! In Origins you have this one little talent tree which is the same no matter what class. There aren't multiple ways to make a healer, there are like 6 healing spells and you take them all and that's it. With mages there is a little bit of leeway but it is mostly a nuker or a control mage. But there just isn't any depth to the combat, most of the mobs die if you just freeze them and then stone fist them and they shatter. Pew pew anything else. When there are huge swarms of archers and shit later in the game, you just do a huge lightning storm on top of a huge fire storm and it zaps them all to death instantly. Some of the auras and stuff are more interesting but ultimately too weak, and not enough of it. Basically it is close to being a modern classic Bioware type game, but it is just too dumbed down.
Also the length of the game was an issue for me, it was too short, and there were also some boring parts. The start origin stories were ok at best and suffered from them having 4 different ones (or however many). After that I did some trash battles, then the mage tower which was fun, then visited some town and got a bunch of quests, killed a dragon, then had a super boring slog in the dwarven mines, and then there was another big dragon and then it ended. I was expecting a lot more.
Overall, not bad, but I hoped they were going to build upon it in the future and it might have turned into a great series. But instead they took an already dumbed down game and made it dumber and dumber each time.
NWN OC wasn't very good, but it is still better than Origins. Also the character building is awesome, especially with multi classing. And the combat is better too because it is just more grown up and has depth to it. And late game it is REALLY good when I am summoning Mordenkanen's Swords and huge fire elementals and having fun with all the big spells. They were smaller than the Origins big spells yet they felt much better, and weren't OP. My only real issue with NWN is that the OC is boring story wise, but everything else about it was good, it also deserves some open mindedness in terms of graphics etc, because it was made as a game that people could make their own campaigns with. So the locations etc, were all a bit fugly and cut and paste, but the upside is far bigger than this minor cosmetic downside imo. I played entire campaigns made by random people and that is really impressive, I also played it online in various forms, mini MMO's and co-op campaigns etc.. Back when internet gaming was still new, that was really impressive.
I really like NWN, also the 2 expansions for it were great. I wished it had a full party instead of the companion idea, but overall I think it is a great cRPG the likes of which you just don't get anymore.