There are many places. I would suggest starting in Google and simply typing in the phrase "Homeschool Spanish Academy Reviews".
Here are a few reviews that will appear:
http://www.onlypassionatecuriosity.com/homeschool-spanish-academy-online-spanish-classes-review-giveaway/
http://forums.welltrainedmind.com/topic/365053-any-opinions-on-homeschool-spanish-academy-1-on-1-skype-lessons/
http://teachbesideme.com/homeschool-spanish-academyreview/
(You'll need to hit ctrl+F, and search for "Homeschool Spanish Academy" but there are some good references here) http://thepioneerwoman.com/homeschooling/what-curriculum-do-you-use-to-teach-spanish/