magura pros:
Light
good selection of pads
good bite
good to modify (eg, grind rims, longer lever blade etc)
no spoke flex
Magura cons:
loud as f**k, can't slow the bike down without making a racket
not very good modulation (no stoppies then)
buckled wheel stops play
need to deflate tyre to remove wheel
not as good in the wet
forks arn't as strong
more maintenance (grind rims, replacing pads etc)
Disk pros:
good modulation
good bite
quiet
good in the wet
forks are stronger
can take wheel out with the tyre inflated
buckled wheels don't matter (as long as it goes through the forks)
maintenace is minimal
Disk cons:
heavier
can catch the rotor and bend it
spoke flex
not as instant bite as a magura
My choice would be disk, I just hate loud brakes