Definitely worth trying, but as of 2010, do not expect anything spectacular other than the unique atmosphere.
Well, as of today, this game has little to offer to someone who didn't live the early 2000 / late 90's gaming scene. I still recommend it to those who enjoy dark, gothic, but not excessively gory or scary stories, with some action. The game is not poor, it is in fact quite enjoyable, but just not what people are used to at this time. Additionally, some basic knowledge on the original Alice in Wonderland story is needed to appreciate this game fully, because it takes place years after, and it assumes that you know what happened before.
But let's talk about it in more detail.
The main aspect of the plot is revealed in a confused cinematic intro at the very beginning of the game: Alice is peacefully sleeping in her bed when fire spreads in her house. Soon after, she's in an asylum, and refuges herself in her "Wonderland". The place is not the same as she remembered though, it is dark, creepy, and violent. Alice herself is different, and way more cynical. There's something wrong in Wonderland, and the cause is unclear. Vague? Yes, it is vague. If you want to know more, go play it.
The game plays as any other standard action/platformer. Alice's adventure is straightforward, the puzzles are very simple to figure out and you'll spend most time jumping from one platform to another and bashing various monsters and bosses, while finding new weapons and following your path to destiny. The adventure is fragmented by pieces of dialogue, usually rather short but pleasing to hear, due to the fact that all characters have a voice over, which for most -but not all- is pretty good.
The game is not too hard if played in standard difficulties, and contributing to that is the fact that you can pop a quicksave at any given moment, making your adventure much more laid back. If you're looking for a challenge, I suppose you could still attempt finishing it in the most difficult mode, but I'd suggest you to first try enjoying a more relaxed experience and living the plot and the unique atmosphere, that so far only this game can deliver.
To sum up, if you like retro formulas of action/platforming gaming without too many twists or innovations, go for it. It's worth it, and it'll keep you hooked until the very end.
For your information, a movie is in the making and so is a sequel, which will be called "Alice: Madness Returns". We shall see how EA will pull that one off.