Originally Posted by
Steve B.
On the current Di2 systems, road and mountain, the electronic cable connections to the derailers are not susceptible to dirt intrusion and resulting tension errors that are common with mechanical.
Any cable is subject to dirt intrusion. No sealing system is immune to intrusion.
Claiming that Di2 "outclasses everything else," including systems that don't use a cable to actuate the derailleur, is nonsensical.