I am looking add external storm windows. Thought about the internal ones, but we get a lot of crap that blows into the window, as we live out in the country. What brand of external storms have people been using?

Use a window with anti-bow rail and anti-bow pins in the extrusions, lift the window the weight difference between good and crap will be apparent.

The very best storms I have seen are LARSON L301 two track. The inserts go into separate tracks so there is no blow in. The hardware is simple and effective.