It is also important to mention that I only understand the concept and rational of the "Rock-Solid Hybrid WordPress theme developed by Justin Tadlock. I must admit that I have tried many times utilizing many other wordpress frameworks, but I must say that Hybrid Theme Framework is the simplest one to understand and very flexible to extend, endless possibility.
Justin developed the following themes based on his "hybrid-core' framework
The first one is the one that I am using as Hybrid Theme for developing many child-themes. Secondly I am also using hybrid-base, but at this point just as testing stage.