This is an rpg with a capital R. The story, characters and plot makes this game still stand out miles a head of the competition. The combat isn't great and the game quickly becomes easy, but that's not really the point. Talk to people, seek information, explore every area - it's well worth it. I highly recommend installing the New Vision mod that greatly enhances the dated graphics.
Where to even start. Immersion breaking at every step of the way. The radiant dialogue reminded me that i was playing a video game from start to finish. NPC's act so weird in this game, a guard that had just watched in horror as his entire town and all the people he knew had been killed by a horde of demons greeted me with joy after i had closed the hell gate that spawned the demons. This was consistent through out the entire game. Everyone is happy no matter what happens around them. Then we have the absolute biggest flaw in the game; Leveling up makes you weaker compared to the enemies. The entire world scales when you level up, and quite quickly the monsters will be more powerful than you almost regardless of what you do. The only way to keep playing is to abuse game mechanics, cheat, adjust the difficulty slider or just not level up. To further exacerbate this problem the loot in the game also levels with you. You will never find anything good, it will always be generic boring items that won't provide you with any sort of advantage. Then we have the dungeons - i think there are three dungeons in the game, copy-pasted over and over again. It gets old, fast. For the most part the quests are boring, There are only a few i even remember as most of them was so generic that they didn't stand out. The combat consists of you hacking and slashing away at enemy damage-sponges. Killing a simple zombie at the start of the game can take several minutes even if you have a good strength score, decent weapon skills and a level-appropriate weapon. In the end i simply ran past enemies. I didn't want the xp. The loot was pointless and the combat was tedious and boring. If you really want to try a TES game go with Morrowind or Skyrim.
There are only two games that challenge this one as the best game of all time, and that is Deus Ex and...Baldurs gate II: SoA. I think Baldurs gate is better than the sequel. Reasoning: I feel like there is a greater freedom in this game than in the sequel, lots of areas with few quests involved, leaving me free to explore the wilderness. Other than that i like the plot in the first game better, since the sequel's plot is really the story of irenicus.