If you pay a little more for a Boss OD20 you get a tube screamer and a bunch of other pedals thrown in for free. I have one and it is a very versatile unit that can go form a mild blues overdrive to full on balls-out dropped octave amp meltdown madness.
My
instructors page and
www.studiotrax.net for all things recording.
my toons Brought to you by Dr BadGAS