Is Ecstasy Motion worth it?

http://www.ecstasymotion.com/

Is this going to be a useful tool for character animation, or is there a free alternative?

(I bought it) It’s a gamble at the moment. On one hand the “early adopter” version is another way of saying it’s in pre-alpha stage(they really should not be charging for it yet). On the other hand, it aims at going up against endorphin wich IS a really good tool for Character animation but costs $10,000 for a single license.
If they pull it off it will be a fantastic thing for indepedent developers(release date set at dec 2009). But at the moment it’s unusable. After release the price will be increased to around double the current price, so as I said it’s a gamble.
Endorphin has a PLE for free, Otherwise check out Dance 4.0 that’s along similar lines but not as user freindly, but is completely free. At the moment from best to worst products would be Endorphin, Dance, then Ecstasy coming in a distant third.
Blender’s game engine will have support for IK in the next release, which I hope will lead to the dev of some motion synthesis tools based on blender.
Motion builder has introduced some ragdoll physics but I’m not too sure on details.

Do you have a link to Dance 4.0?

It is such a generic term, that I can not find it on google.

http://www.arishapiro.com/dance/#download