I was on Verizon... terrible experience.
When I hopped over to AT&T, got a final bill for over $400 (normal bill was ~ $250). Cancellation fees, they said.
I fought it and they finally admitted they were wrong. Got an e-mail to verify.
Then, a year later, I start getting collection notices. Called the collection agencies (they kept passing it on from one to another) and all of them agreed it was not valid and would clear it out.
Until a few months ago (understand that I left Verizon over four years ago)... this agency wouldn't let it go and they put a collection account on my credit bureau.
Unfortunately, I lost the e-mail from the Verizon agent acknowledging the final amount was wrong.
So, I settled with the agency for $125 and it was removed from my bureau.
There is no amount of features or reduction in price that would ever make me consider going back to them... just terrible experience.
Be forewarned!