I'm a little at a loss as far as this one goes. This is the exact same FreeCell as is available for play in the AisleRiot Solitaire game which is also installed by default. It's the same engine, the same cards, the same fonts, the same version number, the same programmers, the same copyright date.
To see if there was anything different at all, I played a game of FreeCell in each. In AisleRiot the icon next to the program name is different from the icon that shows up in that spot while playing FreeCell.
I can only assume that this special double-availability of FreeCell was given so that Windows users could find their favorite program already waiting for. As if grumpy old women are only holding off on installing Linux because they are afraid they won't be able to find a copy of FreeCell that works in Linux, or something. This really seemed pointless, and it made me spend time playing two extra games of FreeCell to look for differences, and I hate FreeCell.
It's odd that they make special mention of FreeCell by having it as a stand-alone entry in the 'Games' menu. Unlike regular solitaire, which compares favorably to its Windows sibling, or the other solitaire games which have no Windows analog, FreeCell is decidedly worse in its Linux incarnation.
Since it utilizes the AisleRiot engine, it doesn't have support for any of the handy-dandy ways that Windows FreeCell makes your life easier. Generating a game from a number, so you can always recall it? Not doable. Double-clicking a card sends it not to the stacks where you're trying to get all the cards, but instead to the one-card slots in the top left, which is both annoying to Windows users, and annoying to people who've played other games in the AisleRiot engine.
Also, I spent a few minutes wondering if my copy was buggy because it let me pick up stacks that should have matched another card, and drag them to the card, but wouldn't let me place them. I eventually realized that it was because I didn't have enough open slots; the Windows version makes that clearer, if I recall correctly. In all fairness, I might not recall it clearly, but I don't ever remember having that problem in Windows, even when I was learning the game and didn't know the rules.
The interface is prettier in the Windows version, as well. Something about the beady little eyes of that king who follows your cursor around is comforting, and the way the slots for storing cards and the slots for winning are seperated just makes it look cleaner; it's more organized. Loading up FreeCell in Linux is an intimidating looking beast because there's no clue to what's what in the layout.
I will probably update this post the next time I dual-boot back into XP, so I can clarify exactly what's superior in the Windows edition, but basically FreeCell in Linux is, while functional, very inferior to the version that ships with Windows. If Windows FreeCell is grade-A uncut pure heroin, Linux FreeCell is a godawful 10th-person-down-the-drug-foodchain, cut with arsenic, nastiness that may get you through if you need a fix, but certainly won't satisfy.
UPDATE: Yep, confirmed. It looks better and plays better in Windows.