Us would be OP. I say no. He's great for a prologue companion, but he'd make animal companions and such seem lame.
And just to have him at camp seems off to me. Astarion makes it clear he's afraid of the "brain things" and rightly so. SH clearly doesn't like them. Lae'zel only put up with Us because it was helping you get to the helm. She certainly wouldn't let it roam the camp. And I doubt Gale and Wyll would approve as well.
I just can't see it being a viable option. To me, it would be pure meta.
