So not to be a tygon whore but.....I am. I've used both vinyl and pvc and they are stiff as $hit and have way to much memory. Tygon is like a baby's a$$. It is soft, supple and will bend around and over pretty much anything. Not to say that vinyl or pvc doesn't work, it just can't compare to tygon. I'm also a cheap bastard, but once I tried tygon there was no turning back....
And no I don't work for any company that distrubutes the sfuff.