Almost certainly the best-written, best-organized core rpg rulebook I've seen in 20+ years of gaming.

While not a lot of support material currently exists for RQ6 -- as of this writing -- the transparent nature of the underlying Basic Roleplaying (BRP) game system means that materials from the Mongoose Runequest II line (e.g. the Monster Coliseum monster book), and even the Basic Roleplaying line (e.g. Classic Fantasy), can be adapted into RQ6 with a minimum of heavy lifting by the Gamemaster.

If you've ever wanted to give RuneQuest a try, start with this edition.

An excellent product in many, many ways. Full marks from me.