Tree's point about traveling is an important one, and certainly a huge one in my experience. Despite my travels in other countries and wanting the robustness of mechanical for that, I know for a fact that my bike has had much rougher treatment in the box traveling, and me getting the dropbars fitting into amongst the frame and all that, cables pulled and pushed, and who knows what other forces in transit with baggage handlers and conveyor belts....
would never want a hydro setup just for this reason!