I was only able fly fly a single leg in a 747. Mostly due to living near the American Airlines mega hub at DFW and being a heavy user of AA.
Late May of 2002, I flew a BA from Heathrow to Changi in Singapore, business class. Departed, if I recall correctly at 10pm and arrived around 6pm in Singapore.
My first experience with BA and it was excellent. Had a nice dinner and was soon asleep and logged 8 hours of uninterrupted shut-eye.
That leg filled in my dance card for nearly every Boeing aircraft except for the 717 (added later in Hawaii)
Now only need to find a 787 leg.
That May of 2002 trip was a one of a kind trip for work. Three weeks long, business class, once around the world to the right. DFW-LHR (AA) , LHR-SIN, SIN-NRT (Japan Airlines MD-11) and NRT-DFW (AA). The MD-11 leg was my first and only MD-11 experience. (Very nice)
Wish I had flown a few more times in a 747.