HI C.,
Well, I may be a bit biased, but I would hands down recommend Hopkins Dance. I was trained there from age 6 (and I subsequently danced professionally for 5 years). The curriculum, compared to the others, is much more ballet based and is very high quality. The teachers are all highly-skilled and very loving toward children- most of them are previous HDC students and are very passionate about dance. Many of the girls who 'graduate' from HDC go on to either dance professionally, major in dance in college, or go on to dance with companies. Hopkins has the ability, and the resources, to recognize talent and passion in young children and nurture it. THe good thing about HDC, as well, is even though it is ballet based, there is also a very strong tap, jazz, modern, lyrical focus.
I loved it and I received excellent training. I would be happy to answer any further question you have or put you in touch with one of the teachers there if you want to pm me.
Good luck and have fun with your little girl!