...at least as pertains to the HAH:

Many of you are familiar with my commute- 33 miles, all highway except for the 1st and last 2 miles. I drive off-peak, so congestion is virtually never an issue in any lane. There are several rolling hills of 50-100ft, usually 1/4 mile slopes, and then the usual over/underpass hills every few miles. Net altitude gain is +100ft for the AM drive.

All last sumemr as I was learning to drive efficiently I used DWL and neutral coasting on downhills, with a target speed of 60mph, minimum 53-55, max 65. I finally 'got it' around late July, also around when the car passed 5k miles, all broken in, and 1st oil change. My normal AM commute FE was 39-41, creeping up in the fall to 40-42.

During the winter I shifted away from DWL and began to use CC exclusively for the 29 highway miles, set at 60. Now that temps are ~same as they were last fall, an apples comparison shows me at 40-42. Actually, its more often between 41-43 the last month, with a few 44.0s as I hit my parking space. This is with CC.

The last few days I decided to try DWL for old times' sake. Yesterday: 42.0. Today: 41.5 (wet roads from overnight rain).

Moral of the story: in the HAH, CC is ~as effective as DWL for FE for those with consistent, relatively flat drives that don't require speed changes. The computers' fuel and cylinder management is at least as good as my foot's, and even better when you consider its holding speed on the uphills, yet still matching or beating my DWL results. Of course, I could be screwing up with my foot, too.