admittedly, I have only ever purchased coach seats my entire life. I have lucked out and been upgraded or traded seats enough that I have ridden in all the other locations, but only for domestic flights. From what I recall, the seats are ever so slightly better in business and economy plus, but that I still can't comfortably sit the way I want to. If I were to pay for anything other than coach, it would be for economy plus or business, but if I were to ever fly internationally I just know I couldn't manage the seats long enough anywhere but first class.
I'm not even tall. I'm 5'8", I just like to cross my legs.