I also had Alta and Sur-Ron.  But sold the LBX to buy a second Alta for my son.  Fortunately, the Sur-Ron has a robust resale value, especially now that you can't get very many new ones from China. 
I did test ride the KTM around the parking lot.  It was certainly fun, just not "Alta fun."  (Plus, it was twice as expensive as the used Alta I picked up, and I couldn't order a second battery for it.)  Easy choice.