Just got the appointment for my fourth one today (Grandfather and father had colon cancer, it killed my grandfather but that was back in 1969).
As others have said, the prep is the worst part, but this time, they gave me an option of a pill rather than the liquid plumber. I may opt for the pill.
Easy procedure and yes, it's a good sleep.
I've always scheduled mine for a Friday, in the morning.
Good luck and don't wait five years to schedule again!