I switched flat bars to bullhorns, and I kept my brakes inline CX style just for ease of conversion. I did also get a slightly shorter stem to accomodate the extra reach out the horns.

I find that I still ride on the flats most of the time, but it's nice to have the option of another hand position. Usually, when I'm starting from a standstill, climbing, or mashing out of the saddle, I'm out on the horns. It helps me get a little extra leverage than the flats. But as soon as I'm up to speed and back down in the saddle, I'm back on the flat, so that's where I keep my brakes.

Two considerations to keep in mind: 1) you might need brake lever shims. My flat bar had a 31.8 clamp, whereas the bullhorns are 26.0, so I had to get shims in order for the brakes to snug down tight enough. 2) you might run out of cockpit space. With my flat bar, I had plenty of room for a reflector and two headlights on the bars--now I don't have any, so I had to move the headlights up to my helment and backpack strap.