I just had a Magura Marta SL brake from late 2007 fail. It appears that the seals in the master cylinder (brake lever) have failed, and they're not replaceable. I'd have to replace the entire brake lever assembly, but they're no longer available from Magura. I'll look on ebay and such, but its a bit of a roll of the dice there.
So I may need to buy new brakes. While I loved my Maguras, I doubt that I'd buy them again because they are expensive. And parts like brake pads aren't commonly available in stock at a LBS.
I do prefer mineral oil over DOT; which Shimano uses. And Shimano brakes are much more common than Magura, so pads and such are easy to find.
Does anyone have a feel for how long spares (would be caliper and master cylinder) are available for Shimano after a newer model is introduced?