I find it funny peoples POV's it should be remembered that pads make more of a difference in braking than the actual discs. They are in their base element a large lump of iron. More expensive discs may well be made of a better grade iron, but its still a stinking thick piece of iron. The grooves and drilling are all there to release heat quicker from the discs and to avoid fading. It is still the pad at the end of the day that makes the biggest difference in braking. Take a patent disc, and you can greatly improve its braking with better pads. Take a good disc and pad and swap the disc for a patent and you won't notice as big a difference. Biggest thing with these discs is a higher risk of warping, or possibly the odd crack, but not enough to stop them working. And nothing a brake skimmer couldn't fix. And your more likely to warp them if you either haven't bedded them in properly, or if you drive hard and then stop with your foot on the brake at a junction instead of using the handbrake.