Basically disc up front is preferred because it offers all weather stopping, with high power and modulation. A magura up front normally cannot rival this power without being grabby a(and usually savagely noisy ). With hard pads and smooth rim, the magura will give th same amount of modulation but offer less power. Most trials ridders still run a maggie on the back due to the positive on / off feel some say that disc simply cannot achieve. I personally run maguras front ( on a smooth rim )and back ( with a grind ) as i like the modulation on the front, and dont really need the extra power. Im running a set of racelines, and love them. most people will agree that hs33s from this era are far better than the 05 onwards due to a far better TPA (Turbo pad adjuster ) design and sturdier bar clamp. For a list of good pads, check the pads revioew section in Trials chat.