Wanted to share a recent experience with Vista Print to perhaps save others from a similar headache.
I recently purchased Premium Business Cards from VP. When I received my cards the paper was flimsy and cheap and the printing quality poor (could see the pixelation). I immediately contacted VP's customer service via the website and was told that the paper is what they advertised (80lb cardstock); the rep said he did inspect my file and because it was high resolution that they would reprint. However, when I responded that the paper was not adequate for biz cards, I received no further feedback. I sent a second message through the website; no response. I tried calling but the customer phone number is only automated; you cannot reach a live person (ever). I ended up tweeting and did get a customer service rep to call me who was rude and did not offer to reprint. He only ended up refunding me the shipping (not the cost of the cards).
Note: I had the exact same cards printed at OvernightPrints and they turned out great (although I was less than pleased with OP's greeting card printing).
This was my first, and last time using Vista Print.