I wanted to share my current experience with cards and pockets because this information would have been helpful to me.
I designed my invitation suite along with a graphic designer friend so we just needed a place to print them. Cards and Pockets has a nice collection of options so I had them print my invites, rsvp cards, and details cards. I also purchased coordinating envelopes with a liner for the invites and rsvp envelopes but c & p does not print on envelopes. We found a printer that could print on the envelopes for a good price and have recently found out the envelopes are very difficult to print on. They are jamming and due to the texture of the envelope they are smudging. I am still 10 1/2 weeks out from the wedding so we have time to find an alternate plan but I did waste a good amount of money and lots of time thinking this could work.
They have fun invite embellishments at C & P but I strongly recommend testing any envelopes you want to purchase from there. If I could do it all over again I would have just found something at minted or wedding paper divas where it is all done for you!