How reliable is itether? I looking to buy an iPad 2 tomorrow, but i'm wrestling with the idea of buying the 3G or Wifi version. I don't have wifi at work, so the 3G would be nice for that, and for traveling. But I really hate the idea of paying for 2 data plans with AT&T. Is jailbreaking my new iPad and using my iPhone's 3G connection an option for those of you that have tried it?