Amazon reviews are sometimes suspect, but people seem to like it:

http://www.amazon.com/Jacks-Hydroponic-5-12-26-Professional-25lb/dp/B00IGYTCGA#customerReviews

http://uedata.amazon.com/Jacks-Hydroponic-5-12-26-Plant-Soluble/dp/B00B9FGNX8#customerReviews

Edit: There also seems to be plenty of discussion in some of the pot forums but my work blocks those sites, so I can only see the google results to confirm that the discussion exists.