Kai Leng was a horrible antagonist. So ME3's story suffers for me cause of him. The DLC for 3 is miles better than 2 though (outside of shadowbroker that is)

I'm going to go with 2 based on the character interactions and story. as has been said, in 3 it was a "let's check in on the old friends" kinda thing.

Although Javik is great.

There's a lot I like about 3 over 2. But storywise trumps all of that and i'm going to go with 2.