We use Vocabulary from Classical Roots. So far, so good. The lessons are short and sweet, dd is expanding her vocabulary, and all in 10 minutes a day.
To me, knowing the roots is much more important than learning the language itself. It isn't spoken as a first language anymore. So for us, a full on Latin program isn't practical. It is too much of a time investment for a relatively small benefit, especially considering the many excellent root programs available now.