I've been testing the effects of riding in the aero position vs. on the grips. Rolling along at 20 mph, when I get into a tuck position, all of a sudden I'm doing 21 mph. That's a nice gain. I have many short stretches where getting into a tuck for 30 seconds on downhills makes a significant speed difference (23 mph vs. 25 mph). Also, I have several long straight flat sections along the river with strong headwinds, and as long as the surface is relatively smooth, I can stay in a tuck comfortably for extended periods.

My overall average speed has picked up about 1 mph for a 15 mile commute. So instead of averaging overall in the 17s, I'm now averaging in the 18s.

So far, the new bars are working out nicely.