Another thirty or so hours questing in the world of Oblivion, one of the greatest RPGs ever; graphics, sound, and story all combine to provide one of the greatest gaming experiences available today; the first expansion that I've played which actually makes the game better than it already was.
Lows
There are no lows that I can think of - there is no reason not to play this game if you already have Oblivion.
Final Verdict
Bethesda came close to the perfect RPG when they released The Elder Scrolls IV: Oblivion. With Shivering Isles they may have achieved the perfect expansion.