Ok, so this is I’m sure a dumb question – but what difference does rotor quality make? Will I notice a difference if I buy a cheap one v an expensive one? Is it mainly weight? Or anything else? Thoughts please…

Well, the Superstar one I have is rubbish (a fair groove at one point, only ground one way so it judders), so yes, cheap ones can be iffy.

Shimano and Magura ones I’ve had have all been spot on. Wavey / drilled should clear muck and gas better, but broadly it’s much of a muchness.

If you want better brakes fast, then better pads and bigger discs are the way.