We ordered from Weddingpaperdiva's and they came in the mail today! They're so nice.
The rsvp cards perfectly match, everything looks great! Our enclosure cards totally do not match at all because I wasn't paying attention when I made them on vistaprint and picked a completely different style by accident. For some reason I was so obsessed with this one style that I somehow didn't register that they don't really go with what our invites look like.
But that said, they still look nice and they fit into the envelope with the RSVP card in their envelopes as well. So we're happy that it all fits together and the printing turned out nice.
Now I just have to figure out how much postage to put on them and the RSVP envelopes. Does anyone have tips for this when mailing square invitations? I tried looking on the USPS website but I didn't have any luck.