My daughter, who is almost 9, and her friends are always playing with them. I think they play with the babies more than the 18" dolls.
My daughter bought the tub with her own money. She loves it. The little accessories are cute. I'm sure you could find another tub similair for a little less, but this is what my daughter wanted.
As much playtime as my daughter and her friends have gotten out of the items I would say they are definitely worth it for her. I guess it depends on how much your child already plays with bitty. Over here it's a daily occurence.