The carrier's new "Never Settle" promotion will give Verizon customers a free phone to play with for 14 days and then pay Verizon's early termination fee for customers who switch over permanently.
T-Mobile offers competitively priced plans and extensive international roaming.
Please see CNET's Cell phone plan finder to purchase a phone with T-Mobile service.
The carrier is also guaranteeing that prices won't increase for customers on existing plans -- even if you're on a promotional program.
Prices for each line range between $10 and $16 depending on the number of accounts. T-Mobile is also bundling a free domain and Microsoft Office 365 services for any company paying for additional data.
The prepaid carrier gives customers unlimited access to high-speed data, but with a few caveats.
Both carriers have similar programs that allow customers to carry unused data from one month to the next, but it's not as simple as it sounds. This is how these rollover data plans really work.
CNET's Dan Graziano explains the difference between T-Mobile and AT&T's rollover data programs.
The Simply Prepaid plan puts T-Mobile in direct competition with its own prepaid arm, MetroPCS, which may actually still provide a better value for some.
A new salvo in the wireless price war cuts the price of shared data on two lines by 29 percent.
The smartphone, which is Sony's answer to popular Android-based devices, mysteriously disappeared from T-Mobile a month ago, and neither the carrier nor Sony would say why.