The prep is by far the worst of it. I wish they could do it differently.
And you get diarrhea-like bathroom runs half a dozen times maybe.
Yes it was annoying to get the runs and gross to drink the stuff the first few times, but people eat things like cow tongue or live octopus or whatever... I can handle some bad-tasting Gatorade and some diarrhea just fine, especially given the 5 years of peace-of-mind it buys me afterward.
The prep was horrible, particularly the electrolyte drink they make you take the night before. I almost puked several times trying to get that stuff down.
Actual procedure was a breeze. I was sedated, and then I woke up and it was over.