It's a really immersive experience and worth buying for the replayablity, lore, open world, realistic NPCs (And I mean realistic as far as how they react to your race and actions) story and combat. The gameplay is just amazing and yeah there are some flaws, like no multiplayer option (there's a mod for that) but if you can live with them then overall, it's an amazing game and a classic in my eyes.
(Review on Steam)

(Edit to original Steam review) Funny enough I never finished the game because I got so stuck on adding in mods. Maybe one day I'll finish it