You should buy the KTM 390 Duke if you are not a strong BMW fan as the upcoming G310R would not be as performance filled as the current generation of 390 Duke. You can even wait as even the 390 Duke is ready for an update in the coming future. You can decide between both the bikes after you go through the pros and cons of the both the newcomers. The new Duke is expected to be more powerful and better looking, inspired from the Super Duke styling.