In my humble opinion, it is better. You can put $15 on every 90 days to keep it active. That is not going to get you a lot of time, but it is cheap. Plus, it is a lot easeir than Trac to load the time. Virgin also has a $90 card that does not expire for a year. That is a great option for a "glove box."
I'm buying a prepaid phone for someone for Christmas who doesn't need it often, so I think I'll go with Virgin because of the yearly card is a better deal than Trac's. Which phone is better, Oystr or Slice?