I've had both. This is a very good example of the 2 bikes. SDR got more power, but R1 got better wind protection over 100mph. I sold that R1 because it was so slow. The SDR is a joke without track mode.
Its not underpowered its just a midrange machine and 100ccs smaller than the Duke. They are both phenomenal machines. Well RC8R, the old rc8 isn't quite as good.