You can join the brotherhood even harder than you could in the base game but some brotherhood NPCs still treat you like you're an outsider?

The main questline also leaves a lot to be desired, it's mostly roughly linear FPS gameplay.

The added enemies (super mutant overlord, albino radscorpion, feral ghoul reaver) all have terminal cases of bulletspongeitis to boot, making the extra ten levels feel like your character is actually getting weaker.