Which properties define ease of use for a Theme Framework? Is it the amount of theme settings in the WordPress admin? Theme Hybrid doesn't have a lot of settings, but it is very educational. I've learned a lot about how WordPress really works and I'm learning to write my own simple PHP functions. Something I wouldn't have seen myself doing a year ago. So instead of making life "easier" with dozens of theme options, it teaches you how to code and style your own theme modifications. This keeps the framework clean and understandable. So for me, ease of use, doesn't really mean anything until someone explains what it means for theme frameworks.
Besides that: what really matters is the ease of use for website visitors. This really got much better since I started using Hybrid.