I was shocked when I opened the box. I ordered 44 cm, and it looked like they'd sent me the child's version.
It took a little getting used to but now they don't feel any different than any other bars. They put me in a more aerodynamic position when I'm on the hoods, I don't feel like it affects my breathing at all. This is mostly psychological but I feel a little more nimble on them - what I mean by that is when I ride in city traffic I'm slightly narrower and better able to navigate through the gridlock, and it feels like that carries over to riding in general even though I'm sure it doesn't. I don't think the flare improves (or hinders) control on gravel.
They route internally so if you use hydraulic brakes you'll need to bleed the lines to install them.