The procedure isn't bad; as you've discovered it's the not eating before and they also tell you to take it easy after so you will be hungry, thirsty and out of sorts when you finish up. The worst part of the procedure for me is the intake where you're all undressed and waiting to be "next" (my doctor was doing them like an assembly line :-) and feeling kind of naked and a bit anxious but I was in a small doctors' hospital that was just for them so that might be different than your situation. You have to wait around afterwards, to make sure you're okay, so I would have them call the cab/whomever to come back then?

Don't you have to drink the special, nasty tasting stuff, several helpings thereof that you can't mask very well no matter how you try?

I had polyps, only 2 (they're often hereditary) but one had cancer cells in it. I haven't been back though; it takes 10 years for cancer to form/be a problem (we all have cancer cells wandering around inside us) so I'm waiting at least until 2013 for my next one. I enjoyed it that much :-)