There's no reason for Oblivion fans NOT to own this.
However, asside from the techinical difficulites you might have, the good things outweigh the bad all-in-all. The price for starters is cheap, and you have plenty of ways to get the game, from Direct Download through the site, to the shelves of major retailers, and Xbox 360 users can get it from the Xbox Marketplace through their system. You get a very well written storyline, that you would expect from Bethesda titles. It lacks in no area other than perhaps its shortness, but for 10 bucks, you get plenty, especially considering the track record thus far in keeping us fans with regular new-updates.
It would be silly to give this game any less than what you gave Oblivion on the rating system. And it would be silly not to own this expansion if you had any love what's so ever for Oblivion.