I'm coming from a biking background so I feel pretty comfortable on the aero bars. I am on them whenever it isn't sketchy (ie hard turns or bumps) or climbing. (I love to see guys climbing on the aero bars because I know I'm about to pass them). Shifting isn't a big deal, just reach over to the brifter and do it. No biggie. (Although if I was shifting more frequently than every 30 seconds I would probably just stay in the drops. Any longer and I'd go to the aero bars.)