Originally Posted by cwtch
At the shop I work at we have Trek which has ISO Speed decuopler on a bike. It is a lot like what the Roubaix has. In my experience we never have any issues with the polymer absorbers.
Di2 wise we have not had a battery fail or warranty yet.
Hydraulic disc brakes on the other hand we warranty all the time. On both MTB and road bikes. It is shocking how many we replace. The parts usually are warranty but labour is not covered.
Not trying to influence you but if worried about Di2 battery failure then don't even consider hydraulic disc. It is 65-75% of our warranty work. The rest being mostly forks and shocks on mtb and an occasional wheel here and there.
Hence my affinity with some good mech discs. If using fresh cables/housing they can be in ballpark of hydro smooth action. I have a coupla bikes strung with fresh stuff connected up to mech discs and it is hard to tell the difference. Of course the levers have to be decent set too.