Botox has made a huge difference for our son. It is definitely worth doing.
Make sure the doctor giving the botox has a good relationship for your child's PT. It is not an exact science, and there needs to be a constant back and forth and how it is working and where it should go.
Also, our son receives Versed (like Valium) before each botox treatment. It helps him forget the treatment so he does not stress about it when it is coming up. I recommend it.
The treatment is very painful. Holding Patrick down while he gets those shots is one of the hardest things we have had to go through as parents. But the Botox has really worked wonders. So even though we have to pay out of pocket for it, we do it.