I was on it for a good while. I started at 40 (great! but I was still symptomatic), then I went to 80 (great for about 2 weeks, and then symptomatic). At 120, I was like "oh sweet baby Jesus, get me out of this body!" Horrible akathisia. We went back down (after 2 hellacious weeks at 120), but it never went away. (And I don't know if that's just a weird thing just for me or what, but it seems like once I get a SE, it STAYS until I'm completely off it.)
When I was at 120, that was before the FDA had bumped up the dosing allowance, so it was kind of unheard of. I think it's been approved for up to 160 since then. My pdoc said she would never do it for a patient whom she didn't think needed it--80 was pretty much her limit, and she only had one other patient besides me that she went up to 120 with.
If at all possible, see how you feel at each dose, and do not go higher than you need to--especially if you find it activating for you. Some people do just fine at 40. Some people are perfect at 80. I'm the only person I know that's gone higher than that. I also used it as a monotherapy, so I have no idea about how it would react if you're going to start Depakote with it as well. Good luck!