nope, I go faster, actually. higher cadence, smoother spin, faster speeds. just try it. start climbing a big hill, just gently place your hands on the bars. spin a gear that you can do 90 in and then...relax your upper body. you have to think about it the first few times. do it muscle by muscle, shoulders, lats, hands, forearms. you'll go faster, becuase you're using using less energy on clenching your upper body.

as for big bars, I like them a lot. I have experienced flex while standing, but it doesn't rally bother me unless it makes noise. and I like ergo-shape bars. so ha, 531.