I was thinking of getting one to use for product photography, I have the 100L, but I do not have a way to get wider shots when I need them. I also had the 90 TS-E which is a close focus lens, but the wider shots were a issue since I could not move back enough.
I do not understand why live view would have any affect on focus shift, unless one were stopping down to manually focus. Liveview focuses at full aperture and then stops down for the image.
I noticed that TDP also has quite a bit about the focus shift. I'll probably pass on it now that I've read those reviews. It is a expensive lens, and my primary use of close focus would be crippled.