Yes they sell brand names and reputable products. They may not sell everything though depending on what you're looking for. I couldn't find the product I wanted anywhere other than through Vitacost so I was quite impressed.

They sell many products others sell plus their own line. The service is great. On any particular product you have to do your own due diligence, but it looks to me that they are trying to sell a variety of product but always include what they feel is top level.

Yes, they sell leading brands as well as their own. I have been very happy with their products. They also guarantee satisfaction.

Yes! Wide variety of brands and always the best price!

Yes, they sell reputable products. I've been ordering for years. Never had anything anywhere near an expiration either. They have premium service and prices. Their bogo deals are great!