Sorry Altair, don't know if the flight was full, didn't look behind me. I am OW sapphire.
For what it's worth, although I obviously am not going to turn down an upgrade to first if it is offered, I don't personally think that first is all that much better than business. You still have to sit in the same seat for hours on end, and that is what I dislike most about flying. I definitely would not pay for first. I probably would not even apply for a points upgrade from business to first.
Economy to business is the big difference in my opinion. Or, private jet vs. commercial service.