Just one other comment, on what appears to be a misunderstanding of the difference between Average FE and Instantaneous FE. The HAH only displays Average FE. It doesn't give you any reading of what your fuel efficiency is right now - at least not without Navi. I can't speak for what additional features Navi may have. So, instead, Honda has given us the ECO light to represent Instantaneous FE.

The HCH and Insight have displays of both Average and Instant. FE; I guess us Accord owners just aren't interested in what mileage we're getting at any particular time...