Ditto. I will accept you and the other folks in this thread, as well as the very fast cutter on television who uses the mat, whom somebody in this thread mentioned, as my validation. I fooled around with this a little bit yesterday and, again,
(1) I can't see the ruler measurements as well as the mat's.
(2) Flipping the cloth around from left to right after the first cut is just asking for misalignment. The mat drags, as it's supposed to, to hold the fabric in place, so it tends to drag a misalignment when I try to turn the fabric.
(3) Both my mats have exactly the same measurements as my clear rulers. (I know this isn't always the case -- you should see the variation among the measuring cups in my kitchen!) Anyhow, for most purposes it's enough just to use the same measure for the entire project, which I do. I'll be using the mat on my big worktable. I'll use my old, smaller mat on my sewing machine as a quick measure whenever it looks like two patches aren't lining up properly, to see if one of them is too short or long. (This really comes in handy, as well as having the pressing surface on the flip side of the mat beside my SM.)
(4) The comparatively wider lines on the mat are not an issue. I just cut on the same edge of the line every time.
I just use the markings on my big, clear ruler to make sure the side of the ruler I'm going to cut against is a perfect perpindicular. Once in a blue moon I use it to actually measure something.