... you want some service or need help.

I usually don't try to safe money when it comes to brake parts. But my SECOND set of (quite expensive) original front disks of the ST suffered from uneven wear when the pads got stuck and as the disks are still thick enough to get them skimmed I bought a set of TRW disks to get the car MOT'd. I didn't expect much for 20 Euros each (one Motorcraft disk for the ST costs about 140 Euros!)... I have to say I tried REALLY hard a few times but wasn't able to warp them yet

As long as you buy parts of a big brand you're usually on the safe side.