Very early since I've only had four rides on them. So far I love the new
setup.
The wheels (Magura Pro Disc Hubs and 317s) don't feel significantly
different from my old ones. They roll nicely and are particularly round. The
build is a little beefier than before (no radial pattern on the front), and
approximately the same weight as the old 517/Specialized front and 517/XT
rear (the new front being slightly heavier and the new rear being slightly
lighter). The most noticeable difference is the sound of the freewheel. It
sounds a little more "Kingish" than the XT, but isn't quite as obnoxiously
loud as a King. They still have a pretty light and spry feel to them, which
I like.
The big difference for me is the jump from my old XTR V's to the Magura
Marta SL discs. I've never run discs before, so I don't have any other disc
brakes to compare these to. In comparison to my XTR V's, the power is
amazing! I really like being able to apply a lot of brake power with just a
single finger. The modulation is also great. I never knew there was such of
range of braking power between off and on. I rode some technical stuff at
Hartman's and being able to control my braking so precisely on those steep
granite slabs was perfect. I'm looking forward to doing some bigger descents
on them as things dry up higher.
I also think they look really cool, so that's important, right? The rotor's
outer edge is not round, but almost looks like a gear with shallow teeth.
The machined inner section is also a very cool looking spiral/starburst kind
of pattern. Not sure if any of this performs any function beyond style (I
suspect it doesn't besides maybe shaving a little weight) but it doesn't
seem to hurt.
The levers are carbon fiber, which have that very trick look to them. In
reviews I've read there were concerns expressed about the durability of the
levers, but no cases mentioned of actual durability problems. In fact, one
reviewer came back and followed up after a year to say they held up well
after some hard crashes. They feel very firm and stiff, which is what I
would want a lever to feel like. I also suspect that colder rides may be a
little nicer with these levers over metals ones that just seem to suck the
warmth from my fingers.
So, the proof will be in the long term, but so far I'm very happy with my
birthday wheels and brakes. They added a little (very little - the brakes
weigh less than XT V's) bit of weight to the Epic, but it's still a very
light bike for what it can do. This gear continues the goal of mine for this
particular bike to be slightly "freeride-ish" without being a pig so I could
still do the occasional fun XC race on it and not be last. I'm also thankful
for a lighter bike when doing some rides that require carrying the bike for
any length of time (preferably not because of mud, but for very steep
ascents). The balance as always is to make the bike light but still durable.
Not being a very big guy (5'9", < 145 Lbs.) also helps on the durability
side. I'm sure this setup would be totally inappropriate for anyone of
freakishly large or heavy proportions.
I'll let you people know if my opinion changes over time.
Matt