1. T-Mobile doesn't have roll-over.
AT&T has rollover and it doesn't last 1 year. If you talk a lot you don't build minutes, and if you don't talk enough you lose minutes. When I had AT&T I was at the cheapest plan I always average 2800 minutes saved and even if the 12 month drops off I still have 2800 minutes saved.
AT&T has one of the best marketing features that was useless. You still have to watch your minutes even if you have rollover.
Here is what available from Verizon Wireless
1) Friends & Family free unlimited calls to any number including landline. Depending on your price plan you have a choice to pick 5 or 10 numbers to include in the list for Friends and Family
2) In Calling - Verizon Wireless offers in calling, where you can call 90M+ Verizon Wireless customers for free.