I love them both! I am only on episode 9 of Season 3 of GA, still way behind. I need to find time and watch the rest to catch up.
I also don't think you can compare House and Grey's Anatomy. They are not the same.
I love the dynamic of the family in Brothers and Sisters. There's comedy, drama, and scandal. It's a very good show. Not sure if you still can but they had all the epsidoes online at abc.com.
That's hard to pick. Hmm... I guess Grey's Anatomy due to the music.