Ask for more money. The salaries you see here are lower than what people are actually paid. Some of the reviews are fake, too.
This company is not a tech company and they do not favor people with technical skills. You will be underpaid and your only opportunity to make more money will be to leave to another company, which sucks, because this is a pretty fun place to work if you find the right fit.
Promotions are difficult to come by and promotion salaries are not negotiable. You will be underpaid if you move up at this company. It's extremely difficult to get a raise no matter how good you are.
There are no "spot bonuses" paid to employees. That is an HR scam to get you in the door, just like some of these Glassdoor reviews!
Training is difficult to come by. The budget is abysmal, something like $300 per employee per year. You can't even attend a day conference for that price.
The tuition reimbursement is impossible to use if you are not pursuing a degree directly related to your job function. No certificate programs are reimbursed, either.
T-Mobile is actively and knowingly violating net neutrality laws. Google Braxton Carter's comments on net neutrality. He's the CFO.
T-Mobile's latest rate plan is not good for consumers. It's really disappointing given all of the amazing things we have accomplished under Legere's leadership.