Avantages
Training and "green days" to work on training courses online, team activities for teambuilding, excellent benefits including up to a 10% yearly bonus (merit-based), tuition reimbursement, extra insurance options besides health insurance (pet insurance, free life insurance up to 1.5x yearly salary), stock purchase options and yearly stock award to each employee. One of my favorite benefits is job swaps - so long as your manager clears it, you can swap jobs with an employee from another related department for up to a couple months to gain insight and experience into what the other department does from day to day.
I left my last company as it had become a bad environment, and after joining with T-Mobile I realized it was one of the best decisions I've ever made. There are very few days where I wake up not wanting to go to work, and I learn something new every day. When I come across a process I'm not familiar with, my teammates are more than happy to provide on-the-spot training, or schedule a time that works for both of us to do so. Above all, the managers set you up to succeed rather than to fail - they want you to do well, and do everything in their power to make sure you have the tools to do well.
Inconvénients
There's some of the same political bs that any company has, but my team has two excellent managers that make work enjoyable. There are a couple personality issues within the team, as happens with any job, but overall everyone gets along. As far as training goes, there wasn't a whole ton initially (though I believe it's more due to the nature of the job - it's impossible to condense everything into a couple week training course).
