If there are two viable strategies in a multi-player game, one involving Goons, then I believe whichever strategy has more players has the advantage. The reason is that Goons players don't work towards ending the game, as they buy a variety of actions and won't empty any pile other than Goons. A lone VP-card player has to buy so many VP cards that he slows down his deck, while the Goons keep going; two VP-card players can end the game much faster, either taking the Provinces or running out VP kingdom piles.
I played a 3-player game with the following kingdom:
Remake, Island, Mining Village, Caravan, Mint, Tactician, Jester, Contraband, Goons, Fairgrounds
This is a very good Goons deck, because there are Tactician and Mining Village to allow you to play multiple Goons, and Remake, Island, and Mint to get rid of unwanted copper.
But with all the cards good, it's also a reasonable Jester/Fairgrounds deck, particularly with three players so that you have two chances to gain cards (both good cards, and cards that will count towards the magic 15) with the Jester. Remake also helps because it makes it possible to get rid of most of your copper and all but one Estate, and possibly to get a missing card later.
I went for Jester/Fairgrounds against two Tactician/Goons players. I got all of the kingdom cards except Mint either in the normal course of events or as Jester prizes; I didn't have a deck that benefited as much from Tactician, but I Jestered one, and also Jestered a Goons (and bought one later). My 15th card was a Duchy.
The problem is that I was the only player buying lots of greens, and thus I couldn't bring the game toward an end as I greened my deck. I was ahead in VP, but I could only end the game by buying Fairgrounds (and getting all 12 would take forever), or by giving up lots of VPs to buy out another pile. If there had been two Fairgrounds players, we would have had six each and then run out the Duchies or Islands if necessary.
The Tactician/Goons players were taking Tactician turns and playing several Goons with the help of Mining Village; a typical turn for the winner was Tactician, MVx2, Goonsx3, buy Caravan, Mint to trash a bunch of money, and three coppers for 15 VP. This was an ideal setup for mega-Goons turns.
Meanwhile, a typical turn for me late in the game was to discard two cards to a Goons and then use the remaining three to buy a Fairgrounds for 6 VP, or to play my own Goons and buy Duchy/Copper for 5 VP.
I was actually ahead in VP on my last turn, 71-66, with two Provinces and six Fairgrounds for 48 of my points, but the next player ended the game with a 17-point turn, buying the last three Caravans and two Estates. The other Tactician player had only 48.