Heh: it's almost bigger than my character. Tears through a deathclaw like nothing else.
Oddly enough, despite the intense coolness, Vengeance ended up going in Luna's megaton locker. It seems every character I play ends up using 'Ol Painless and the Wazer Wifle, regardless of what is available. She reached Vault 87 (or was it 78?), freed Fawkes and cleared out Raven Rock using just those two weapons.
I too have favorite guns, I always use Sydney's ultra 10mm SMG and if you're addicted to psycho, there's not much stronger aside from the alien blaster. But the very best gun for takin' out the veritbirds is the Tesla Cannon. I race to get to Adams Air Force Base just to get the damn gun! I love it! I laugh manically while I shoot all the veritbirds and everything else in my path.
The problem with the SMG is keeping enough bullets around. Then again, I gave it to Jasmine, so that might have been what the problem was. Every time I turned around, she was out of ammo and using her "old" hunting rifle.