I thought the main benefit was that they are stiffer and resist expanding under pressure - so when you press the pedal, more of your energy finds its way to the calipers instead of going to waste stretching the rubber hoses.
I've fitted Goodridge ones to previous cars - Strada Abarth and Golf Mk1 16v - and found them to be a worthwhile mod as it does make the pedal feel firmer and the brakes more responsive, even in everyday road use.
Personally I think the DC5 brakes feel a bit 'wooden' and this might address that. I've got some Spoon ones for my DC5 which I haven't fitted yet - part of my large collection of 'attic jewellery'