I tried out T-Mobile as well earlier this year. I was actually impressed with the speeds around Greenfield, like Hwy100 and Layton, but their in-building coverage was not great. In Waukesha at my work, I had to hold my phone up in the air to send a text message. Also, T-Mobile's coverage was horrible in Muskego, it dropped to edge almost the entire time driving through or hanging out there.