Vantaggi
This company is great if you are looking for a great work/life balance. The company does not work people to death. You have plenty of time to relax. You can start out with a lot of vacation even in the first year. The company recognizes great performance and puts a lot of effort into celebrating those successes. Working with people at T-Mobile is a very positive experience as well. The company is successful in generating a good team work environment. People are usually very open to help you.
Svantaggi
For a finance guy it can be very frustrating seeing every day how much money is wasted. There are a lot of good things happening at T-Mobile. But if you want to be a successful technology company you need to write software in-house. People have a lot of good ideas about how to improve business and it always stops (or drastically slows down) because the IT department is a protected monopoly. Your are also less empowered at this company than with others. Getting more free time comes at a price - gaining less experience and getting less exposed to new challenges.