My wife and I just returned from Mata Chica, and we both give it glowing reviews. It's definitely out of the way: you can either take a 10-15 minute boat trip or walk almost two hours from town (often along still-damaged beaches).
I think the location is great, and boats to town are easy to come by. Nadia and Philippe are very warm and welcoming hosts. You should have a great time. Don't miss out on the amazing snorkeling and diving in the area.
I also recommend a dinner at the Rendezvous (a 5-10 minute boat trip away). I saw a posting here a while ago that really slammed it, but everyone in our group of five thought it was excellent.