As a beginner you'll probably find the little Ninjette very easy to move around, both riding and not. Try to avoid the freeways at first and learn how to ride, speed doesn't teach that, practice does.
The other two are on the bulky side, okay power-wise but clumsy at slower speeds.
About 10,000,000 people have learned how to ride on the 250, can't be that bad, right?!?