Hi,
You need to walk over the aisle passenger to get out if he's flat. Not impossible to do without touching him/her but definitely no space to avoid "jumping over". Also consider FA passing food etc if your companion is likely to sleep from the start.
Advantage of window seats are a bit of extra storage, and the windows obviously but I prefer to seat on E and F seats (when in couple) and have direct aisle access.
I personally prefer the first cabin, just to be as far as possible from screaming babies at the beginning of economy cabin. (But I'm quite partial to baby crying for 8 hours...).