Yes, I am a big fan of the Tokyu Stays, especially for...stays as opposed to quick visits.
I think they'd be especially good for families with a small child or two, given the in-room washer-dryers and kitchenettes. In fact, when I spent a month in the Monzen-Nakacho property, there was a family living there. I saw the four of them at breakfast every morning, and if I walked out early enough, I could see the children being picked up by a van that had the name of one of Tokyo's international schools on the side.