Testing 17-40 L refurbished
The 17-40L is a very solid lens, extremely well built and reliable and it doesn't need IS. It works seriously well with the 5DII, where its excellent microcontrast and subtle colours balance the slighty contrasty sensor of the 5DII. I prefer it to my 35 f1.4L on that camera.
The main thing to check is de-dentering which can be a problem with WA zooms as there are so many complex elements. My copy has very slight de-centering on the left side. I've never sent it in for correction because I've heard of so many people who sent them in only for the lens to return even worse!
It's a lovely lens; its only weakness is soft corners from 17-20mm at large apertures but there is no perfect zoom out there. You'll love it.