Hi all, long time lurker, first time poster. I got the rulebook yesterday, read a solid 50% and skimmed the remaining 50%. I haven't played RQ in something like 18 years, but am a long time player of its cousins Cthulhu and Stormbringer. Having said that, here's my initial take:
The core rulebook is 10 times better organized than anything Chaosium puts out (and I say that with love for Chaosium). The graphic presentation is good, not great, but good. The paper stock is low end. If you have bought any of the new Warhammer rule books, you will notice that the cover stocks are identical, but Warhammer uses a much nicer stock for the internal pages. The content is light, and splitting the rules into a core book and a companion was a bad call on Mongoose's part.
As for the system, I don't have any problems with it so far. It is definitely related to older RQ and its cousins in the BRP system, but a little different, and that is ok with me. I am not sure what people are looking for when they call the system old or say it doesn't modernize RQ, the system for a pen and paper RPG isn't like software that can become outdated and unusable. The value of a RPG system is in whether the players can enjoy it or not, and so far I think I will enjoy this system.
I am looking forward to the Glorantha specific supplements, and I think this material might be the bits that old RQ die hards might enjoy more than the somewhat generic core rulebook.
Overall I'd give it a 3.5 out of 5 with lots of optimism for the future.