I don't have a problem with it but EBC does if you want to maintain the warranty on the rotors. You've got to use EBC pads on their rotors at least through the warranty period.
Hmmm, I didn't even look at the warranty. Found this on their website:
"Warranty is for replacement of similar product or refund of purchase value only excluding all labour and ancillary charges such as collection, fitting, inconvenience, purchasing of other manufacturers products and is valid for a period of twelve months from date of purchase or 5,000 miles of highway use. Warranty is invalid if product is used for racing, trackday experience driving, or any other form of competition. There is absolutely no warranty on any EBC product for race use. Riders must assess the performance and durability of EBC Brakes products themselves if any EBC product is to be used in racing. EBC also strongly recommends the use of its own EBC brand brake pads to run with the EBC rotors and numerous other aftermarket brands have been found to damage EBC rotors. The EBC rotor and pad is sold as a matched set and developed to work together, do not risk damaging your rotors with using a pad that may damage your new EBC rotor product."
It says "strongly recommends". I think I'll risk it and use my OEM pads.