Great review, I just converted my custom theme to Headway last week. I'm using the beta 1.7 too and the features it has are pretty unbelievable. There is a quick start video, a setup wizard with default styles and a lot of improvements and added features that make designing easier but still with the flexibility of custom CSS and easy hooks. I just changed something in 2 seconds which would have taken me 5 minutes on my custom theme. Not a huge deal but over time the effect is enormous.