I used Dial 7 (used to be known as Tel Aviv) based on recommendations from this forum when I was there on my last trip. Big mistake! They charged me a "peak time period" rate, and a "waiting charge" (even though I was there on time and the driver was late, and didn't know how to use his Nextel phone to call me and tell me where he was). They were rude on the phone when booking the trip and wouldn't consider reversing any of the charges. The trip they quote as $45 turned out to be $75. What a huge rip-off!
Also, contrary to other reviews posted here, the driver did not have an EZ Pass. It took forever to get to the airport. I don't know a whole lot about NYC driving, but I doubt that the roundabout route the driver took was a very efficient way to get to the airport - it certainly took forever and didn't seem to avoid any traffic. But like I said, it was his first day.