I was in 13K on the 787 last week, when you recline you hit the back wall. BUT, I don't think you lose more than maybe 1" of recline at most. I found the tradeoffs well worth it to get a window seat - there is a full 3" along the side of the window seat, enough to store a 1.5L bottle of water and a stash of newspapers and other reading/listening material.