I've also used the Canadian version of Vistaprint many times. I like them although I wish you could customize the back of the folded card. There is one thing I've done with them that helps the cost. I should say that I've only used them for small note cards rather than 5x7 cards, which are more expensive. But when you have an account with Vistaprint, they frequently send you e-mails with deals, often daily. Often the item is free - in the case of small note cards, it would be free for 10 cards and then you pay the shipping and tax. I've actually found that it is cheaper to place separate orders and buy 10 free cards at a time and just pay the shipping/tax than to order the full amount in one order. Anyway, just wanted to mention it - that is my little cheat with them. It may not work if you're looking at the larger cards given that they aren't offered for free (I don't think so anyway) but I thought I would tell you about it.
I've also done folded note cards at WHCC and really liked the quality. I recently used a small flat card from WHCC in the art watercolour finish as a thank you card and they were beautiful and quite reasonable in price.