Honestly, I stayed at/got married at the SunDiver, which is one resort south of Mata Chica, and I was not impressed with Mata Chica, esp. knowing how expensive it is. It looked so much smaller than the pictures on the web, and I don't think it had a pool, which, in my opinion is a MUST. Plus, it's quite far from town, so be prepared to take a boat to get to town. You will be pretty isolated. I LOVED the SunDiver and the isolated location, but some of our guests didn't like taking a boat everywhere.
You will LOVE your wedding experience in AC!! Congrats and best wishes!!