If you are single and enjoy long blocks of time off, it is ideal. Even more so come vacation time Obviously only a small fraction of pilots would like this option. I am one of them.
And the attitudes on this board are simply disgusting. Oh wait, this is FI.
Just did PBI-BED today in 3+30 with the majority of the flight at FL390. Fuel burn was 2200lbs. Not too bad for a screw job.
Looking at flightaware there was a Citation 560 that did it in 3+10. Not too big a difference and I am sure our passengers enjoyed the cabin a lot more.
What temps are you using?
Where does your rudder trim line up in cruise?
At 16K you should be well into the 260 KTAS range. At 23K, 245 is about right.
How hot has the OAT been at cruise? The airplane is a dog in heavy and hot conditions.