Paycom is Epoch is Paycom.. Its like the egg and the chicken..
As basschick have said, both have their pro's and con's... Both are trusted processors.
Epoch could have better integration of all admins and options available to site owners. (psst.. And somebody should do some redesigning for their sites...
)
CCbill: there are a whole bunch of possible affiliates who refuse to use CCBill because they say their overal ccbill stats suck.. It could cost you business..
Right now, thumbs up for both processors...