Completed it myself, I think it's the best DLC pack for ME2, and possibly of any game. No it doesn't compare to the sheer content and quality of GTAIV's 'The Lost and the Damned' or 'The Ballad of Gay Tony' but it is all you want for ME2. Exciting action and pushes the main story on in a significant way. They say this will effect what happens in ME3 and I can certainly see why. To top it all off, there's some great looking areas, the best boss fights I've played in ME2 (so far, still not completed the main story yet) and it's got a humourous script with nice inside jokes, as TD mentioned. There's a good reward for completing it, I daren't say what it is but let's just say you'll find out things about characters that gives them a little more depth or are just laugh out loud funny to read.
In short, I'd absolutely recommend it to anyone who's invested in the universe of ME.