I just joined up to the first one you mentioned out of curiosity, I didn't know any existed since the poorly functioning and ultimately doomed Aspieaffection. But at least every person on AA was real, they may have signed up years ago and their memberships expired but they were all real people - I remember talking to several people on there before it stopped working.
But this "Autismdatingservice" could not be any more fake and scammy. None of the members are actually aspies, they appear to be either fake profiles or lifted from some other site (which the company also operates no doubt).
Even with these fake/misplaced profiles, there are very very few people on there and the price for a functioning full membership is outrageous.
Remember that the excellent OKC is free! and has a great App. There is also Tinder, and if for some reason you wanted something basic and full of perverts/prostitutes, then there is also plentyoffish.