They’re 80g heavier and around €90 (approximately £75) cheaper than the RT8s. A full set of callipers, levers and hoses has a claimed weight of 578g and will retail for €529 (about £425). Apart from the material changes, the design is essentially identical to that of the RT8.
Magura say the advantages of hydraulic brakes are that you can brake later into corners, saving some time. Also, hydraulic cables can bend more than mechanical ones, so can be installed in tight spaces inside the frame.
The RT6 TTs will fit standard road frames, but if you want to use them with road brake levers you’ll need a converter.