In all honesty, paying F for First on UA is silly. It can be argued that the return on the investment flying paid F on SQ or NH is not worth it - and those two airline's products (especially NH's new service from JFK/LHR/FRA) make UA First look like Economy on United Shuttle.

I would not even pay C and upgrade via a SWU. If you have to sleep, the First Suite is a great benefit. But I view that as the only benefit of UA First over UA Business. And since I can't sleep, I'll never see a Suite unless I am op-upgraded to it.