In my opinion, platter mats are like seasoning of very fine food. Each palate will react differently to one particular choice or another. And fish requires different seasoning compared to beef stew. Although each of us like to think of ourselves as a searcher for the Absolute Sound, and although most of us believe that such a Holy Grail actually exists, I think in fact we are all prisoners of our own senses and biases. Therefore, I would make no definitive pronouncement on what is the "best" mat, although I think we can all agree that rubber mats, and maybe also rubbery mats, are not so great (to put it as diplomatically as possible). Also, within this argument about mats there is a minority who prefer to elevate the LP above the platter (e.g., the much loved Resomat), which is like saying they prefer no mat at all. So this is why I am not blown away that Noromance does not like the Boston Audio mats (whereas I do) or that someone else doesn't like metal mats of any type, or etc. Likewise, I would have to try Slaw's mat for myself before giving it a thumbs up or down. I am by the way, blown away by Noromance's ability to give precise numerical rankings in 4 categories for each of about a half dozen mats, especially since in every category, all the mats ranked >5, on a 1 to 10 scale. So the rankings are really on a 1 to 5 scale. Seems to me the nature of the platter itself, of the drive system, and of the other elements of the turntable, tonearm, and cartridge are critical co-determinants of the end result. So Noromance's rankings are only relevant to his turntable, tonearm, and cartridge, not to mention his phono stage/amplifier/speakers/room.
