The music might be decent in game, but I will pass on casually listening to it.
After playing the Elder Scrolls games, the tracks get old. You can add your own music tracks and there are some well made music packs that you can download from other modders. Adding the right music can especially enhance the mood while exploring ancient ruins.
Musical taste is subjective. If it sells, any negative comments here are irrelevant. I'm sure most music sold on iTunes wouldn't hold up to being played over and over while people played a game for long hours over the course of a year or more. And if you think you have music that is better, then great use it. But don't think for a second that the millions of other gamers will agree with you.