I got ride of the 2x9 driveline on my bike, and switched to a 1x11 using an MTB rear cassette and derailleur. I live in the hilly part of Tokyo, and rides to the west coast of Japan involve a fair amount of climbing, so a wide range of gears is necessary. I find it easier to shift up and down with a 1x system, and the bike is cleaner without the extra shifter, cable, derailleur and chainrings of a 2x or 3x driveline.