I was actually fairly scared that I wouldn't be able to deal with it, being generally claustrophobic and crowdaphobic, but it didn't bother me at all. The noise that the machine generated was incredible - my pulse actually synced with the background thumping. Then there was the different pitch and frequency of the vibrations (which set the bed rumbling). If the mattress was nice and contoured rather than being hard and flat, it might have felt like a gentle massage system!
They were playing 80's music, but thankfully Madonna didn't get played - that would have been too surreal. I had to have two tests - an abdominal MRI to find my left ureters (they have never been found ;>), and a pelvic MRI looking for endometriosis and adenomyosis. For the pelvic one, an extra device was placed on my stomach and I was strapped down.
Sometime towards the end, I got pulled out of the machine to have contrast solution injected - they hadn't told me about that beforehand, and they made quite a mess of the injection (my veins are bad enough at the best of time, let alone after a nine hour fast!) This test cost a fortune, and I have been told that Medicare do not provide a rebate on it _at all_ (AU$320). I get the results tomorrow, after my next ultrasound in Clayton. It was so much nicer being on a health care card - I didn't have to pay anything then :-\