It's a personal thing, and budget does play a part, but I never use non-genuine filters where liquids are concerned. Remember that your rotor filter spins at 15000 rpm. Would you trust Britpart with such a critical component? Maybe, but I won't risk it.
I may consider one of their air filters, but I have a K&N anyway.
There seems to be no middle ground with Britpart in that the quality is either great or terrible. My only 2 Britpart purchases are a radiator (which seems spot on) and a cellular steering damper (time will tell)
TONY