I purchased the latest DLC for Mass Effect 2 yesterday. I played it through in about one sitting in about 45 minutes. I will admit that some of the reason behind buying it was for the S-Rank but the other reason I bought it was because I loved the original game so much. I played through the whole game in a few days. I haven't had so much fun playing a RPG in quite some time. The classic space opera story combined with the entertaining gun play made Mass Effect 2 one of my favorite games of all time. 
 
Even though the game itself is completely awesome, the DLC is another story. Yesterday I downloaded the new guns, armors, and vehicle expecting to get sucked into the wonderful game all over again. The weapons were pretty lackluster and the missions with the hammerhead was really shallow. My bout with disappointment continued with the Kasumi DLC as well. Kasumi is one the same level as Zaeed because of the fact that you can easily tell that there was not as much time spent polishing the back story of these two in comparison to the rest of the Normandy Crew. 
 
I still love ME2 but as of late, I've not been satisfied with the DLC offerings. I'm still waiting for the "far reaching content" that supposed to show up some time next year. I know its asking a lot but I want the Dragon Age treatment for Mass Effect. Expanding the character with more skills and diverse weaponry would go a great deal to enhance the game. Another addition to the already colorful cast is not necessary. I hope that one day I can play an expansion pack for Mass Effect 2.

Yeah I agree the DLC is not up to standard and is effectively useless to most of us who've already completed the game and will only be useful for new plays. 
 
I just wonder why Bioware can't give us dragon age style DLC, the whole extra new campaigns they seem to be getting I hear.

I'll admit, you only get the full force of some of the DLC if you're doing a whole new playthrough. Kasumi was a bit overpriced. And it would have been best if all of this was available right when the game was released. But most of the Cerberus Network stuff has been free, so I can't hardly complain. I still think the Hammerhead missions are more like betas for content to be included in Mass Effect 3. They're not really meant to be full missions, just tests. Again, it's free content, so what can I say?
 
But I'll second what Garrus is saying and hope that we get some Dragon Age-style expansions. Then again, Mass Effect has only been out three months, so maybe this sort of thing is coming in the future. It is what I expected the Hammerhead stuff to be...

What Mass Effect 2 truly needs right now, at the minimum is a " Point Lookout" or "Return to Ostagar" size DLC pack, but what would be nice is a full on expansion pack. As Kasumi and the Clothing DLC shows people are still willing to pay if the price is right.

I expect an expansion pack in Q4 of this year to remind everyone what the GOTY is.

I'm waiting til right before ME3 is released to play all this DLC. By then, I hope the paid DLC is all free or part of a package deal.