I have the Switchback full zip. I'm 5'8" and 145 lbs and wear a Large in Ibex tops. Loooooong arms and Loooooong torso and sort of wide shoulders.

My Switchback *is* flappy and loose on me, but I wear it as a jacket over other clothes so it's ok.

The length on it is perfect. I've been finding that Ibex sizes are pretty standard across the different styles. All my tops are L and all fit great.