The only aftermarket mat that I have used, which pretty much always results in a better and more pleasing sound, is the Funk Achromat. One exception is my Thorens TD-124 where the original 60s hard (and ribbed) rubber mat is clearly best, at least to my ears. The simple truth here is that different mats alter the acoustic impedance interface between LP and platter, and that alone will change the sound character - whether for better or worse is a personal judgement so, as ever, YMMV.