"Solitaire" card games are not that difficult. Therefore the bar is set somewhat higher, particularly for one that you have to pay for. Solitaire Forever falls far, far short of this bar.
1) as a previous poster mentioned, the menu bar. It's nonexistant. Some preferences, Game-New Game, ANYTHING would have been nice.
2) There are bugs. No less than 3 times in the game I played (normal Klondike), there were perfectly legal moves that it would not let me do, 2 of which may have salvaged the game. ITS NOT THAT HARD. Spend less time making fancy 3D Graphics and FIX THE GAME FIRST. Get the source code to a game that works. SOMETHING.
3) It costs money. I would be surprised if anyone is willing to pay $25 for solitaire, even with pretty graphics.
Positives about this game? It's pretty. And....that's about it.