We have not been to personally experience it...but I have read several threads and did research and talked to my "techy" husband (because we also want to talk to the kids while we are at CSA in May and we have I-phones, pads, pods.
Yes, as long as you have a Wi-Fi connection then you can FaceTime for no charge. Our plan is to turn our phones onto airplane mode when we enter the plane and they will not go back to regular until we are back in the states. This will avoid any roaming/data charges from our carrier and we can connect to the resort WiFi to chat with kids, emails, etc. I have read that the WiFi can be spotty in some areas, but strongest signals are in the check-in lobby area, some rooms and a computer lab room that has regular computers.
Again, I want to disclose that we have not been, but this is the information I have gathered.... hopefully someone who has can chime in to confirm this is correct.
We just visited CSS last month and we talked to our kids through FaceTime every day! It was great! It would work best if we were near the computer/game room , but we didn't have a problem talking from our balcony either. Have fun!!