This is what I am now using on my SL-1700MK2. Actually, I'm not sure if this is the exact mouse pad or not (my girlfriend bought it locally somewhere), but it looks very similar and matches the description to a "T".
http://www.bonafidereviews.com/review-of-artisan-kai-g3-hien-soft-large-mouse-pad/
It's fairly heavy and is just about as thick or exactly as thick as the stock Technics mat. The rubber backing on it sticks like glue to the platter, and the soft, lightly textured top side keeps a firm grip on the vinyl. Add to that my 1 lb record weight and it makes for a pretty good combination.
With many more hours of use now, I can tell that the midrange is a little more open and the bass has a little more weight to it, but still detailed. I haven't noticed any change in the treble. The background seems to be quite a bit "blacker" as well. I think the extra openness in the midrange and the "blacker blacks" has helped improve the width and depth of the sound stage. Nothing super drastic, but certainly noticeable.
The BIGGEST improvement that this mouse pad (record mat) made though is the fact that it completely eliminated any and all static charge on the vinyl. And I'm talking like 99.9% removed too!
Fuzz and dust no longer get attracted to the surface of the records, the plastic sleeves don't stick the records, and there's a major reduction in "pops and clicks" from static. In fact, when you pull the record off the mat to flip it or change to another album, there's ZERO static "snap" heard or static attraction of arm hairs felt at all.
I say you guys owe it to yourselves and your systems (which some are much better than mine) to try this out. It might just be the last mat you ever try.