I didn't play through to the end of the game after completing the DLC (mostly because I strongly dislike that "defend the missile battery part of the London mission)
I actually like that part. It's just a "survive for 4 minutes" kind of countdown, so you can either run away from the banshees, or see how many you can take down before time is up. Then again, I like how crazy challenging and non-stop the ending is.
Not as good as the ME1 or ME2 ending though. ME1 felt incredibly epic. I still remember the first time I went running up the Citadel Tower. ME2 was far more intense, you weren't really sure if everyone was going to make it (I got Legion killed the first time through).
Anyway, I'm still playing through Leviathan. I enjoyed the screaming husk head more than I should have. I kept poking it like a feces analyzer no matter how much it screamed.