I have a KeyCard and a POP Card. I use the POP card more though. I use Go North East when heading into County Durham, Consett and Middlesbrough e.g. But when I am in Northumberland, I always use Arriva. For £1.35 more, I don't mind. For example, if I'm travelling from Ashington to Blyth it would be a total nightmare with Go North East. I would have to get a 19 from Ashington to Cobalt, then a 309 from Cobalt to Blyth. However, it would take me about 30 minutes on the 1!
I personally don't mind what company I use. I don't mind Arriva, but prefer Go North East!