all I can say is the 1 disc wavy set up I have on mine now (thx for the lend 'the Dentist') is way better than the std disc that was on there and works well
They are priced slightly differently. Apart from that, I think they are all pretty good (certainly good enough for a DD bike). I think in order of Cost, Wavy are cheapest at around 150ish including VAT. The Galfer/Braking ones are around the 180-190 mark including VAT. Not sure if anyone has them any cheaper.