I've used run-of-the-mill binoculars (maybe $60 ones) to look out the window. Aside from feeling like a real dork, the experience was okay. You can see pretty well but looking through two panes of typically not-so-clean glass hampers things a little. Don't expect to see individual people from cruising altitude but you might see some interesting stuff. On a trip to Hong Kong, I saw terraced mountainsides pretty well.