I have been using ADV Care for over four years and have been delighted with their consistent top notch service and quality products via postal delivery to the US.
They are very strict about legalities and protocols. For example they insist on annually updated prescriptions (not electronic, but hand-signed scripts) and have in the past communicated directly with my cardiologist's office. They also need all of the proper documentation for mailing cross-border. However, getting these items all in place had not been a burdensome task and they cheerfully walk you through any problems encountered.
The medications I get are completely legit (eg arriving in foil sealed blister packs from a well known large pharmaceutical company with lot numbers and expiry dates in a sealed box with the full product insert included. I also have observed the effect of this medication and it is exactly the same as the product bought from a local US pharmacy chain store.)
The only reason that I have not given "5 star" ratings for all of the categories is that their website is not completely easy to use for this non-computer guy, and that their fulfillment process (although transparent and thorough) sometimes takes a day or two longer than I would like....but has always arrived in less that a week after an order.
ADV is a pleasure to work with and I have recommended them to several friends here in North Carolina who have both reported great satisfaction to me.