I joined EAA in late 1972, when I began building a Rand KR-1. I eagerly awaited each issue of Sport Aviation , especially the October (Oshkosh) issue. Every year there were new designs and adventurous builds. I loved them all. Most articles covered design and building techniques and their roles in the new homebuilts featured in each issue. We got to watch Steve Whitman, John Thorp, Burt Rutan, John Dyke, Pete Bowers, Richard Vangrunsven, Christoph Heinz, and many others develop their ideas and watched as their planes took flight. EAA helped me a lot with my own homebuilt project, educating me in building techniques and how to deal with FAA and inspections. I devoured past issues of Sport Aviation to learn about materials and tools. As time went on, EAA became a powerful advocate for general aviation and those who loved flight outside the corporate ranks. They still do this job admirably. However, with the advent of composite kits and aging of the original EAAers came something much akin to what has happened to much of R/C. Those modern composite "homebuilt" kits really press the limits of the 51% building rule. So while the modern homebuilt aircraft often surpasses equivalent factory craft by large amounts in performance, there is diminished building/designing adventure compared to what we saw for decades, and the magazine reflects this. Large photos have replaced some of the informative text of earlier times. It is still filled with good information, but...well, not as much for the grass-roots builder/flier. After 46+ years, I finally skipped renewing my membership. I have reluctantly given up my earlier dreams of flight in my own plane and don't see my interests reflected much in SA anymore.
Well, those are my musings, although I still recommend EAA as a great organization with a caring staff.