I'm already paying for 3 lines on T-mobile, paying another $30 just for this seems absurd. I rooted my Nexus One to have my-fi like tethering and so far I'm enjoying it. The major trade off is that I'm sure wifi is not the most battery efficient way of using the Internet. But hey, there's always an outlet and cheap chargers out there. My speeds are probably not the best, I think my upload is sometimes faster than my down. How else is everyones tethering experience? $120 + $30/month for wireless use? Not for me.