I think the attraction of Suffusion is that people think they can design a site without knowing anything about CSS or PHP. Almost all Suffusion styling is done by choosing options from menus, altho anything not menu-selectable must be added as CSS in Custom Includes. New users rave about Suffusion because they feel they don't have to learn CSS or PHP and they post rave reviews before they run into the snags in this framework. It's true you can get by with the menus - until you want to do something a little different, not out of a can.
The creator of Suffusion put a lot of work into this theme framework and makes it available free - big appreciation on both counts is due. However, in fact the menu system is confusing, with related settings scattered between different menus so you are never sure where to look. In addition, he has been generous with tutorials - but the problem is that he changes his mind about what to call things and where to put them from one version to the next. It's a nightmare trying to find what some of the tutorials apply to because the name of a function or location has changed and he has not updated the tutorial.
I have never had as much trouble making things work as I have with Suffusion. The final straw was when I left a question on the forum asking what I had done wrong that I could not find my CSS stylesheet and got a snide answer telling me "We are not here to instruct people on how to use CSS". That was not what I asked. I could not find the CSS stylesheet and knew it had to be a wrong setting somewhere but was unable to figure out what I had done wrong in my setup. In other words, my question was about Suffusion setup, not CSS.
So I find nothing at all to recommend about Suffusion. I gave it two stars only because of the immense work the author put into it and because he gives it away free and because he has made it extremely configurable - if you can figure out how to use the menus. For me, CSS coding is easier. But in terms of usability, Suffusion gets zero stars from me.