I have owned a ktm duke for 2 months and this is my experience
Pros-
excellent performance, good handling, good looks, fun to ride
cons-
pillion seat is not very comfortable, the handlebar grips are uncomfortable, needs experience to tame!
mileage - my bike has given 34-40 in city and 40-45 in highway
onroad price- Am not sure about present price
Overall the bike is fantastic but you need to be responsible on it.
Not suitable for beginners: arguably good bike’s are not meant to be your learning console, in this case if you are in the process I would advice you to stay away.