Originally Posted by
Bacciagalupe
...
The Touring models are basically the 800 with slightly different software.
AFAIK it lacks things like speed and cadence sensors, so it only uses GPS for those. It can't use power meters, and lacks some of the training features. It adds some routing/POI options that are probably superfluous on a brevet.
As long as you get good signals, the Touring model is probably fine. I'd still buy it from somewhere with a good return policy.
The Touring is for navigation, not training (there is no support for speed/cadence/power sensors). For an extra $50, the Touring Plus adds a barometer (more accurate elevation gains) and support for a heart-rate monitor.
The Touring software seems to follow the 810 and precede the 1000 (based on user-interface, routing options, and when they were released). The Touring adds "funky" routing options, which the 1000 appears to inherit. These options would not be applicable to Brevets.
It appears that people have more issues with the Touring and 810 when using calculated (turn by turn) routing for uploaded courses than with the 800.
Navigation only uses GPS (the wheel-rotation/speed sensor isn't used for that).