Parents need to know that the subject matter of the lyrics is mostly benign and at times even positive. However, there are some mature lyrics about love and the powerful desire to fit in and be fashionable. The music is also more mature than most kids' fare -- similar to Destiny's Child or some of Prince's arrangements.
There were 3 songs I didn't think were suitable for my 5 year old, but the rest of the songs were pretty good. Alot was sung about friendship, and being yourself.
And my kids love to dance to The BRATZ, so all in all I like.