I've flown first class a few times from SFO to ORD when it was the only thing I could get with my miles. The first time I flew, it was amazing -- personal, fully reclining leather seat, my own movie, great food, no waiting, the works. This was on a 747.
Every other time I've flown it's been on a smaller aircraft, and first class was really just a glorified coach with a bit more legroom -- basically a slight step up from flying jetblue. Totally not worth it.
I'd investigate the equipment being flown before you make a decision.