Its all about if its worth it to you. I would NEVER pay $275+$490=$765 for one way in FC on EWR-PHX flight out of my own pocket. RT, maybe, OW, never (unless its an absolute emergency and I have no other choice).

That said, another question is if you are flying US or CO. If its US, don't even think about doing that, absolutely horrible airline and dispeakable "service" in both cabins (how do you like drinking your $4 a bottle wine from Big Lots in a plastic cup in "First Class"? This is not a joke). On CO FC is very decent, but not for $765 one way for myself.