Pros: GREAT customer service, affordable prices and nice service.
Cons: None so far!
Summary: I've only had T-Mobile for 3 months, but so far it is the best cell phone service I've ever had and I've been with Cricket, Verizon, Cingular and Sprint. I got my T-Mobile Wing for FREE with a 2 year service agreement and so far haven't had a problem.
CUSTOMER SERVICE
I've called customer service up to 3 times in one day when I first got my phone just for questions about billing and features on my phone and there was no hold time, the reps were polite and very helpful and answered all of my questions clearly and thouroughly.
PLANS
I have the TMobile fav 5 with 600 minutes. I have talked over 2,000 minutes with one of the people on my fav 5 in one month and of course there are NO extra charges because fav 5 is unlimited! I originally started with the 1000 minutes plan but only use about 1/5 of that during peak times so I went down to 600 and they didn't try to get me to resign my contract or give me any penalties at all! They will even pro-rate your bill to the beginning of the cycle as long as you call before the statement has gone out so that you don't have any overages or if you used less than you thought you would.
I also have the unlimited data plan for 19.99 which is AWESOME because it's almost just like having the internet in your pocket. You can check your email, go to any website on the web and even use your telephone as a modem for you computer and get online on your computer under the data plan. I had unlimited data with my sprint razr, but I still had to pay $3 a month just to use aol and I could only go to the website that sprint allowed me to. It DOES count as text messages when you use the instant messenger, but I have unlimited text messaging anyway for $14.99.
BILLING
TMobile mails out your bill a couple weeks before it's even due and with that is included a complete phone log history of who you talked to and for how long. Also, the bill you pay is for what you've already used and not for the upcoming month like some cell phone companies!
TROUBLESHOOTING
I DID have something go wrong with my phone and have to call customer support to troubleshoot it, but after trying several things we finally fixed it in 45 minutes without me even having to go to the store.
INSURANCE PLAN
The insurance is 5.99 a month and that covers if the phone is lost, stolen or obtains any damage (Yes! Even water damage!). There IS a $100 deductible for my phone, but since I got the phone for free and it's retail price is actually around $400 that's still a pretty good deal to me.
All in all I give TMobile a HUGE thumbs up and I hope that they never change.