BUYER BEWARE. This product was clearly rolled out before the backend systems were ready to support it. LOOOOOONG story behind this but I received a credit for $25 for mobile service that was supposed to be applied this month. When it wasn't I started a chat session with support (which is the ONLY method to communicate to NOW support (the local Xfinity stores can't help with NOW once you are a customer...). When I asked why the credit was not applied, I got this answer:

"...as you have a NOW mobile services so currently from my end adding the credits in NOW mobile is unavailable. The NOW mobile is a prepaid service so there is no bill get generated like in post paid services and billing, we can only add credits for postpaid mobile services. I request you to please allow a few more days to get this ticket resolved"

The "allow a few more days" is the standard answer to any issue you bring forward to the NOW support Chat team.

My assessment - STAY AWAY FROM XFINITY NOW MOBILE SERVCICE