ifman depends what Modeller your currently using to if CharacterFX is actually worth getting.
alot of people find it easy, the thing of it is that really it's very basic and doesn't offer a great deal over Milkshape of any of the other budget programs animating abilities.
gameSpace has trueSpace's animator which is ridiculously simple to use, seriously as all you do is put down the bones and voila you can start animating immediately. No assigning, not IK fiddling nothing.
if you have one of the higher end programs they're not as easy to learn to animate within, but they are infinately more rewarding ... as they have better options and physics engines for thier IK which makes movement quite realistic.

To Survive You Must Evolve... This Time Van Will Not Escape His Fate!
900mhz | 256mb | FX5200Ti 52.16 | Dx9 | WXP-Pro