TOEE follows ad&d 3.0 rules and the setting is straight out from the Grayhawk module of AD&D.
Pros: nice graphics, not bad sound.
Cons: Bug-ridden, incomplete and severely inbalanced. Most voice-overs not very decent sounding.
My opinion: It's kinda fun although quite a few of the bugs made it difficult or impossible to proceed with certain areas or quests. Some areas were extremely boring(same for some of the quests) and also, I felt that while some of the stories were brilliant, some of the others just bored me to death.
Some areas of the game were absolutely ridiculous(the fan-released patch added an area, a brothel which had been removed and I didn't see the point in designing such an area in the first place. They should've put in some more stories or some other interesting features).
Well, Hasbros pushed forward the publishing date of the game, meaning that quite a few areas had to be taken out. This also meant that many of the bugs were not fixed.
My advice: get the game a few months later after they have released another patch for it. Or, skip this game and get something worth your while like Planescape Torment or one of the Buldur's Gate games.