This DLC fails to be the last great piece of content for Mass Effect 2.
It's not too hard and I completed it in two hours. That's right, I paid $7 to play for 2 hours. I could have just gotten myself the Arsenal Bundle for +$1.
The major problem is that it's not THAT interesting. In Zaeed's DLC you got to know about the Blue Suns and his past, in Lair of the Shadow Broker you got to know who he was and with "Arrival" you learn that Mass Relays are not so indestructible? B*tch Please...
But the most disappointing thing is that there is a trophy that requires stealth, which is broken in this game. Just don't shoot or sprint, stay in cover and hug the walls and you should be fine.
Not everything is bad, though. You get to play as a robot, pretty much like in KotOR II, play against the clock (yes, at a certain point you got and hour or so to finish the DLC).
On Insanity fights can be a bit of trouble, but nothing like the Collector Ship mission.
In conclusion, "Arrival" is a short DLC that should only be bought if you love Mass Effect, otherwise spend the money on something else.