The seat is much nicer,
The GFL in SFO is sooo much nicer then a UC...
The food is pretty much the same
The service is a little better

Its worth experiencing it once just so you know if its worth it to you in future

On a 747 on a daytime flight with WIFI, I have always justified it because I have been able to work through the flight and bill >5x the cost of the upgrade

If its a night time flight and I just plan to sleep for most all of the flight I don't know that I would bother