I just bought the first edition of MGR, but I plan to check out the newest revision when time and funds permit. My primary interest in MGR, though, is not as a system for roleplaying in Glorantha, but as a more fantastic BRP alternative that I can use with the CoC Dreamlands sourcebook to create an utterly alien swords and sorcery experience.
As much as I love CoC, I think that the system is pretty much crap for playing in the Dreamlands (which are equal parts surreal fantasy and heroism that the CoC rendition of BRP uttterly fails to capture). My plan is to use the basic character creation rules from MGR, plus the new skills from the Dreamlands book, to better model the Dreamlands as I have come to think of them.