Was lucky enough to get a 2012 8.5 DS last week, and as there does not seem to be too many reviews of these bikes, I thought I'd write a little something.
Changes from stock version:
added Bontrager H2 tires
Thudbuster ST seat post (taken off old bike)
added platform cleat pedals -- my feet were sliding right off the stock pedals, plus they spun like there was sand in the bearings
LBS swapped tires and pedals for free (pedals are normally $90), so that was pretty cool.
I ride 30 miles per day, one trip, 90% road and 10% hard packed trail. Roads where I live are notoriously poor; city council admits neglecting roads to the point where they are basically undriveable.
I bought the 19" frame, even though I am only 5'8"; I've always went with this size frame, so it's what I'm used to. There is no stand-over clearance, but I'm not feeling squished when standing over the bike either. LBS guy recommended 17" (maybe 17.5", not sure on exact size), but I tested 17" in 2011 model and liked the 19" better.
Ride -- nice on smooth pavement, but on rough pavement I do feel it in the shoulders. Made the mistake of trying to ride on gravel and had my bones rattled pretty good. I can't comment on the ride without the Thudbuster, which does it's job nicely (actually cannot imagine riding a hardtail without one). Bike steers well on the rough pavement and is solid enough to take some pretty hard hits, but I try to stay on smoother roads.
Shifting -- shifters work nicely, FD shifts very easily. RD shifts well, except for taking 3-4 seconds to shift into smallest cog (2 trips back to LBS have improved the shifting, but it's still not where it should be).
Brakes -- exceptional stopping power. In my mind, hydros are a definite improvement over rim brakes. There is a long downhill bridge in my city; riding down the bridge one can easily top 40 mph, and the brakes stopped me dead in under 30 feet for the red light at the bottom. I felt completely safe at this speed, even when the bike was hitting bridge expansion joints, which were a pretty hard jolt. (Normally I am easy on the braking, I just wanted to see what they could do). Riding on the walkway alongside the bidge, I can easily keep my speed low without brake fade while navigating around pedestrians. Front brake gets a little noisy towards the end of my ride, then is quiet again the next day; am thinking of finding some better pads to see if that helps.
Saddle -- it's actually fairly good for me. Could be about half inch wider with a little more padding and a shorter nose, so I will be getting a lady saddle very soon. LBS has about 50 different saddles in stock and will allow me to ride one for a few days before buying it, so that's also pretty cool.
Overall, I am pretty impressed with this bike. It is much lighter and faster than what I am used to (other bike is a 24 speed long wheelbase crank forward cruiser). I can comfortably maintain 22-25 mph on the middle chain ring (haven't spent much time on the large chain ring, as my legs are still getting used to pedaling down instead of forward, as on my other bike).
That's all I can think of for now, but if anyone has specific questions, I'd be happy to answer them.