Animatronics vs. Computer generated characters

[Andrea]

Fawkes was done with Animatronics (except, I believe, him flying 
through the chamber)
The Basilisk was done with both computer generated effects and 
Animatronics (pretty easy to see where)
Dobby was entirely computer generated.

It would have been hard to create Dobby without being computer 
generated (except a large puppet) but I think Daniel had a harder 
time reacting in scenes with Dobby because of this (vs. Fawkes and 
Animatronic Basilisk). 

I guess it's just personal preference, but I would rather the actors 
interact with something that is actually there in the room...
Is there a large cost difference between CG and Animatronics? 
How about Blue screen with wires vs. CG Quidditch? 
Any thoughts from the masses?

-Andrea/Kattrap