Thanks for the kudos everyone. It does ride very nicely, and the power is instant, due to the Mikuni flatslide, and it is abundant, though it does not rev. It is a low and mid-range engine in terms of power.
I am going to keep the DRZ, because I am fortunate to have one son who rides with me on occasion. We will be going up to Silverton, Colorado in August to ride the passes there, so he will ride the DRZ, and I will ride the 790. If we want to pair up on a more big-bike kind of ride, he can ride the 790 and I can ride the ST.