My wife and I might fly JetBlue SFO-JFK next June. She might need wifi access during the flight, for work. A couple of questions:

1. Mainly, how reliable is the wifi for tasks such as emailing, website access, etc? I realize that no in-flight system is totally reliable. But in the experience of any folks here, is it usually available on 90 percent of the flights? 80 percent?
2. I'm also curious about whether folks using wifi/skype for conversations in-flight is possible and allowed. I actually hope that the answer is no, and don't think she'd need it. But we still would like to know.
3. I assume that the wifi reliability and speed must the same in the main cabin as in Mint. (It's hard to imagine how they would be different.) But could anyone confirm this?

Thanks for any help.