I am definitely fighting the wife over the unlocked price so I can get one. I seem to be winning so I might be getting one.
I have had T-Mobile for since '05, and I have never had any issues. Every year so far, I have gotten a new phone, 3 out of 4 have been full upgrades (supposed to be every 2 years) and the other was a partial. I have had exceptional help from customer service as I have a phone on my plan that resides outside of any T-mobile coverage (its actually funny, the phone runs off ATT towers... on a T-mobile plan... go figure). I have only had 1 dropped call in the last few years that I can think of. I live in Dayton OH, and we just got upgraded to 3g about 3 months ago. I am quite happy with T-Mobile. They are making giant strides to improving their network.
Edit: On a side note, I have used T-mobile extensively in Georgia(3 years), Texas(6 months) and now Ohio (6 months) and the network has been great in each of the locations. Also, having driven up and down the east coast at least 4 or 5 times from Vermont to Florida, I can say that the T-Mobiles network has been great, at least near the major highways. Heck it even worked great when I was in Alaska for a month.
Rooted Black G1 (Retired)
Rooted Nexus One
Rooted Plum MyTouch4G (Wife's phone)
Rooted G2 (my phone)
Thanks to all the devs who have allowed me to use their product!