After carefully considering the pros and cons of both motorcycles, it is best to stick with the BMW G 310 GS if you have already made the booking. This is due to the fact that the BMW G 310 GS is known for its reliability, comfortable ride and intuitive features. The KTM 390 Adventure is good, but it is not as reliable as the BMW G 310 GS. Therefore, cancelling the existing booking and opting for the KTM 390 Adventure may not be the best option.