I bought a set of the original Magura's when they came out in '96 or so. I think they were HS22? The yellow ones. They are outstanding brakes. I would prefer them (and any road rim caliper) over the 105 discs on my road bike.
However, the SLX discs on my modern MTB are the best bicycle brakes I ever had. They're stunning, I wish my 105's were that good. I don't know what the deal is, all I can think of is the bigger front rotor on the mountain bike.
But as you can see, expect smart ass comments if you dare speak negatively about discs
