If anybody answers that, how you want it answered,well i give up mate. Tis all down to your ears. Any given mat will (or maybe not for that matter ) have an effect on what comes out of your speakers via your TT *. Im sure some Rega lovers will say you really need the Rega mat, but again thats subjective. My advice,if you want to go down this route, is to try a few different mats if you can possibly do so.
* i.e. Tighten up the bass a tad or lift a slight veil off the mids a little or what have you. Or even have no effect, that you can (can't) hear, whatsoever. Basically you have to experiment im afraid,in my opinion of course.
Try the Funk Acromat, by former Pink Triangle owner/ designer Arthur. It has better matching to vinyl resonances than acrylic mats/platters. There is also the Acroplat, a complete platter assembly made from the same material called Aerated Poly Vinyl, made specially for Rega decks. This mat/platter turns vinyl resonances into heat within its structure more efficiently than former acrylic platters - even Pink Triangle ones and they invented the acrylic platter !
I agree with the Floyd Droid. Unfortunately you are not going to be able to audition a TT mat without actually buying it, and its your ears at the end of the day that will / may / may not hear any difference. You are going to have to 'suck it and see' although I wouldn't bother. Spend the cash on some new vinyl!!