I have the Origin 8 bullhorns on my commuter bike - bought of Amazon - but you can find them in LBS as well.
To go along with them I have the Cane Creek 200TT brake levers - also bought off Amazon.

It's my first bullhorn setup, and I like it, but I wish they had a little shorter reach (the bars). But I'm short, so, ymmv

the setup doesn't effect braking at all. its not really any different than being on the hoods of drop bars, except you can actually grip the brake levels instead of just hooking with a few fingers.