Well, one cannot accuse Bioware of being reluctant to support Mass Effect 2 by releasing new content. Since the release, we have had the Cerberus Network provide us with free weapons, two free dlc packs for some users that pre-purchased the game and a new character that was added to your party on the day Mass Effect 2 was released. There was also the previously mentioned Hammerhead Pack. In addition to the free content, we saw the laughable release of a costume pack (for those who want to see Jack in shades) and the recently released Kasumi dlc, which is essentially identical in nature to the Zaeed content, with the exception of a $7 price tag.
Kasumi is for lack of a better term, a thief. She is a master of stealth and uses her optical camouflage to aid her on her various criminal missions. When the Illusive Man realizes that Sheppard needs powerful allies on his/her team, he suggests recruiting Kasumi. Kasumi is found on the Citadel and is encountered in a rather unique fashion. Essentially she is on a quest to steal a device which contains not only memories of her dead lover, but also might provide information required to determine just why he was murdered to begin with. This mission serves as both her first mission and her loyalty mission.
As a character Kasumi seems to fit in well with Commander Sheppard’s misfits, providing a powerful stealth ability that can lead to some fast, effective kills in combat. While she does provide some scripted moments that fit into the story itself, you will see that she has no role in you prospective romances and her input is about on the level of Zaeed.
As far as the content included, I found myself taking just under an hour to complete the mission and that mostly because it had been a while since I had actually played Mass Effect 2 and could not remember all of the commands.While this starts as an interesting heist caper, it quickly descends into a series of large rooms that fill up with enemies, before moving to another large room with more enemies. While it is rather easy to play through, it does at least feature a small boss battle that was fun to complete.While I felt the content fit well into the game, I would have preferred to have had at least one more Kasumi mission and at least the option for romance. Having completed the game, these add-on characters are fun, but just seem to tacked on when compared to the full fleshed-out companions that I finished the game with.
In answer to the main question of whether the content is worth the price, well the answer is yes and no. For somebody like me, any Mass Effect is often better than no Mass Effect. I would buy just about anything short of new costumes that Bioware releases and am what some would call a Mass Effect fanboy. So for the real fans out there, this content is a must-have. For those who are not quite as sold, I would wait until either more content is released and get it all at once, or wait until the price lowers a little. So for most YMMV, but I did enjoy my time here.