Anyone had a problem with GC's Lately?

Has anyone had a problem with the GC 450's lately? my buddy has sent back like 8 valves cause of different prblems? im wondering cause im baggin my truck and i originally wanted the GC's cause theyre louder and have a 3yr warranty but he said i should be lookin into parkers now cause "they are over all a better valve"and theyr warranty is only one year less. i guess in a way price doesnt matter to me cause the price diff isnt that much between them. thanks for your help