You can rely on getting paid reliably and on time if the pay site is using CCBill's affiliate program, or some other 3rd party program that pays you directly. On my pay sites we don't write the checks to affiliates since we never see the money. CCBill takes it out and before they pay us and then they pay the affiliates.

Not sure if other credit card processors have this feature, but you can rest assured if the pay site is using CCBill.

The other thing to keep in mind is the history and track record of the pay site. Do searches on this site and others to see if there have been problems with the pay site.