Completely joint, although I handle all the bills, savings, etc.
Our incomes are within $5K of each other, so thats not an issue. Even if they weren't, I don't think it would be an issue. I am quite a tightwad, and she likes to spend money on stuff I may not agree with. I won't lie, there were some arguments in the beginning, but we don't have any secret expenses. If she wants to go spend $250 at the mall, so be it.
I recently set up our budget for a very realistic measure of what we want to do. I don't spend a lot of cash each month outside of essentials.
We put about 20% of our income to retirement/savings, about 20% goes to taxes, 40% to monthly obligations, and 20% spending cash. It works really well for us, as I am very big into saving/investing, and she likes her mall trips.