Thanks all for your input. The main reason for going with discs on a commuter/tourer or any bike for me is rim wear. Winter riding on the rainy west coast eats rims with "v" brakes for breakfast. I am tired of replacing rims with worn out sides. I want to set up a pair nice rims on the new ride and want them to last for a while. Hydraulics? Well better feel, stronger, no cable stretch, and we all have to admit...wow factor. However after reading some owner reviews on another site, I am re-thinking the hydraulic aspect. Lots of issues around mess, maintenance, cost, set up etc. Maybe the Avid BB7 is a good option.
Any more thoughts on these?
As for mineral oil vs DOT fluid: DOT is vehicle fluid and meant for very high heat and pressure, nothing a bike will ever face. It is messy, toxic, hydroscopic (absorbs moisture out of the air - that large container you buy and use a few ml out of very year or two could well be contaminated by the next time you use it and water is corrosive in the system) and it destroys paint if it dribbles and is not cleaned up quickly.
sth