I'd been playing Runequest since the second edition (the red hardcover), so
most of the details were familiar to me. What wasn't familiar was the
stories -- back then, the mythos had barely gotten started, let alone had
expanded to such a vibrant, colorful world. (We used RQ as a
swords-and-sorcery setting like the Conan movies, not anything tribal or
even vaguely historic.)
Even nowadays I still have fond memories of the original Chaosium system --
even though it was somewhat derived from the original D&D system, it still
had enough innovations to make it seem new. I wonder if someone's
considered converting the system to OGL D20...