Fun thread!
Hmmm...where do we begin?
Schon: Archer won a LOT with a Schon cue. Reid Pierce won the U.S. Open with a Schon. I think Jimmy Wetch played with a Schon as well. Alex Pagulayan won his world championship with a Schon - and although it's been in dispute, I think he was using a normal shaft and not a 314.
JOSS: Nick Varner/Mike Sigel in the 70s/80s. JOSS won a ton of tournaments between those two. I saw a guy in FL run 9 racks with a Joss sneaky pete in a big tournament (he broke with a house cue). He later took 3rd in a US OPEN 9 ball (he had a fancier cue by that point). If he took pool seriously he probably would have been a real champion, but I think preferred cards.
Southwest: Allen Hopkins played with one in the 80s and was considered the best. Of course all of our far east Champions love a Southwest.
Predator: All of the British/Euro champs love Predator, and now many American players.
Falcon: Nick was the first big FALCON player. He switched from JOSS to Falcon, then to Meucci, and then back to Falcon. I remember in one tournament they listed him as sponsored by Falcon, but noted he was playing with his Meucci as he was still adjusting to the Falcon. Jeanette Lee played with them and also Oliver Ortmann I believe.
MEUCCI: Ok...tell me if you remember this, "Because sooner....or later...it's gonna have to be a Meucci!" (This was an ESPN commercial for Meucci cues. In this period, Efren (YES - EFREN -- and he used a Meucci when he beat Earl in that legendary race to 120 or whatever it was), Nick Varner (and he was a big winner with his Meucci), Kim Davenport, Buddy Hall, Tom Kennedy (YES, he was on their AD as well..not sure how long it lasted), King James Rempe, Danny Medina (long-time Meucci player...ran 9 racks in one tournament breaking and playing with one), Tony Ellin, David Howard, Allen Hopkins and many more won a LOT of dough with Meucci cues. I've seen a lot of good players use Meucci's over the years. There used to be an ad in Billiards Digest and half the pro tour was using Meucci cues. Shannon Daulton won the Derby City 9 ball one year in the early 2000s using a Meucci Olympic model. Oh, and our young sharpshooter SHAW put some marks up on the board with a Meucci.
So....if I had to pick the MOST winningest....I'd still say Meucci has an edge over Predator.
(excuse the grammar, I just scribbled this down)