Which cell phone service is better? T-Mobile or Verizon?

I currently have T-Mobile and I'm pretty satisfied with it, but I'm thinking of buying a new phone soon and possibly switching services. Anyone have pros and cons about the two?

Before getting new cell phone,Make sure your phone is Support CDMA networks or else Support GSM only.If you own mobile support GSM carriers only means,you can't use Verizon network service on your mobile.But you will be able to use T-Mobile service.At the same time,Your phone should be unlocked one.If it's locked by particular,You will need to unlock your phone.For unlocking visit Unlock-Zone.com Here you can unlock your phone at low cost.