You are right. Not popular on Autopia nor on any other sites either.
Like you, I did find Presta at my local auto paint store last month sitting next to Meguiar's, 3M, Collinite. Presta offers many different compounds, polishes, waxes, pads, mf towels. So I bought their 8oz Aurora Hand Glaze (hand or PC application) for $5 to try out. When I used it, it reminded me of 3M's IHG in its use. Good shine, easy on but a pain to remove. I looked at their label and sure enough it has Kaolin Clay just like IHG.
The girl behind the counter told me that Presta is popular with only some detailers and that their extensive line is as rich as 3M's but priced lower.
Bottom line...Presta has lots of competition going against it with the likes of Meguiar's, Menzerna, PRO, Einszett, Poorboy's, Zaino, Klaase, Mother's etc...
Have you tried any of their products?