Magnum windows don't seam to pick up much, except the back. it's always filthy. Aerodynamics, no flow...
As for bugs, I think that has more to do with time of day. And if your near water, can be really bad.
We have lots of bugs here near the forest preserve...
My bug zapper goes nuts at night... If I don't clean it every two or three days, the carcasses build up and then the "new" bugs can't get to the wire screen that zaps them.... There's a pile of dead bodies under it all the time...