Originally Posted by
mmff
Besides, I also read somewhere that 17G is not a "real" window seat (meaning there is no window). Can anyone confirm this is (hopefully not) true?
In my experience the window on 17G is slightly offset to be more behind you than normal. When you recline your seat the window aligns much better and you can look out without trouble. However when the seat is upright you'll have a more restricted view through the window.
If you have the choice between row 17 and row 21 I'd personally recommend row 21 having been on both recently.