I use aerobars on the trail quite often. Pretty nice to have, just be sure to swap back to your regular hand positions when nearing pedestrians, kids, dogs, etc that crop up here and there.
Just 2 weeks ago some dude accidentally let his leashed german shepard get loose literally 3 seconds before I got to him, and I T-boned the dog. Luckily, I'd been prepared and had my hands already on the brakes. I slowed enough to avoid damage to the dog and the bike and stayed upright. If I'd stayed in the aerobars, there's a 100% chance I woulda gone over the bars and who knows what could have happened to the poor dog. He was just so excited to see a cyclist he wanted to run out and say hi I guess.
Use aerobars safely and you'll grow to love them. Eventually they become very comfortable, and (can be) aerodynamic enough to get you an extra 1-2mph.
Last edited by jmX; 10-22-12 at 02:07 PM.