I fly SFO-SYD 2X per year, for the last 8 years, all on business.
I've GPU'd to C about 95% of the time, in all seasons.^^^
While I prefer the upstairs C on the 744, I have to agree with previous posts that the reliability of those old birds has really deteriorated. I've been delayed numerous times as well as spent nights in both SYD and SFO for flights that have gone mechanical, not to mention wall panels falling off in the head, overhead air vents popping out of the panel, etc. etc.
I hate to see the upstairs go away but if it means a more reliable plane, I'll take it.