I definately prefer more symmetry. ...all at once, rather than one arm at a time, or somtething bizarre like that. I could imagine one hand shifting a little faster than the other, but not to the extent where one hand is a paw, while the other is almost, or entirely still human.
There is a talented artist who goes my EDMOL who draws transformation images, but one thing I never really liked about his style was his preference for drawing characters this way, with One arm fully changed, but the other completely normal, and a sort of "half way" change in the face, with a portion of the face still completely human. Like
this.
I think that the trasformation would begin everywhere at once...but different parts would change at different speeds, so the fur might fully cover the body before it takes on it's new shape, or vice-versa.
I think it might be cool if someones transformation allways began with one part, like maybe his left hand would allways begin to change first, followed soon after by the right and everything else. ...but not to the extent that Edmol does it.