Thanks for the review because my internet connection is so slow so I can't watch the demo clips of the Builder theme.
I really want to know if Builder will finally suit my need.

I'm not a web designer/developer. I learn how CSS and WordPress template tag works by reading the tutorial, copy&paste code example, and trial&errors.

I bought Thesis and Flexx theme but never use it on the live site due to many reasons. (and that's a big bucks as a regular meal in Thailand costs ~$1)
I'll think as I buy it for learning's sake :)

My current theme is not fixed width nor fluid that stretch across the screen. It's flexible width by the power of YAML CSS framework.
(I'm obsessed with flexible width layout and tons-of-widget WordPress theme :P )
I see Builder provide custom width option. I wonder if I can apply the YAML CSS' flexible width to the Builder theme.