When I was developing my first theme for WordPress, my concepts on using template-tags and template hierarchy were not completely clear. Then I looked into the source code of this theme, and with the great amount of docblocks and inline comments, I got myself running in no time. I would recommend this to anyone new to WordPress theme development :). Just how you have made "everything" possible to override in a child theme is more than amazing.
A lot of options for a free site and most of them are easy to understand and configure. For some reason, it centered all my tables, which was very inconvenient.
Visually terrible site - VERY confusing and unclear.
I like this theme and the author has provided lots of little help tips to get going with it. There is a lot to like in this theme including a wide variety of looks with it's own library of styles included.
One thing that was/is difficult is that header images are poorly implemented. Don't count on changing them the normal way. Here is a thread with solutions to adding header images to this theme with very little work ..