We used Invitations123.com (PrintMall) for our wedding invitations. The first few proofs had typos in them. We had to ask a couple of times to have the invitation text/design altered to what we wanted.The customer service was not very professional and they clearly employ the wrong people for transcribing the customer's text, since two other couples I know had the same exact issue with them. If you're careful and review everything twice, you'll be happy with the final product. The price is also very reasonable. It just took a little more effort than we thought.
The Print Mall was able to turn over our request quickly and efficiently. We were on a budget and were able to get beautiful invitations for a low price. When we had issues, such as ink smudges, they ran new batches of invitations on the spot for us so we wouldn't be delayed in sending out the invitations.