To answer the question what the best MAGURA disc brake for your bike and riding style is, we firstly recommend that you define how your bike will generally be used.
The chart below will help you to decide.
The situation on the disc brake market for bicycles isn't really different to that of any other consumer products.
In fact it is virtually impossible to offer a disc brake for all possible demands, unless of course the weight factor is not a consideration.
Therefore, it should be obvious, that a featherweight like the Marta SL shouldn't be doing anything on a bike used for free-riding, especially if rider and bike easily weigh in at more than 100kg/220lbs.
The best all-purpose qualities are indicated in the column "Tour". Here the weight to performance values come close to being optimum