I've got a few questions,sorry if they've already been answered.
First: Epic DR vs. Mythic, Does being mythic mean you can ignore Epic DR or do you still need a +6 or better weapon.
Second: Legendary Items, If you take the upgradable ability on a weapon or armor can you only increase it by +1 or can you add special abilities to it. For example: If I have a +1 sword can I add the flaming special ability or can I only make it a +2 sword.
Third: Mythic Skill Focus, It says I can take 10 or 20 anytime even when rushed of threatened, so if I have Mythic Skill Focus (Diplomacy) can I take 20 at the start or even in the middle of a fight and try to convince the enemy to be my friend. Also, I assume that you still get the bonus from regular skill focus (+3 or +6 to skill if you have enough ranks).
Overall I like this book but I do have a few issues. For one thing the book seems like it should have been longer, Legendary items should have gotten a whole chapter with example items and some more abilities since most of the abilities can only be taken for minor or major artifacts. It would have been nice to see some more paths or at least some more universal abilities. I do like some of the universal abilities and think they might be good to use as rewards above and beyond the path system. A GM might decide that you can't take divine source as a path ability, you have to earn it by completing a special trial. If you complete the trial you get the ability for free, of course it would be a very difficult trial. If you want to improve it you have to complete additional trials. This allows PC's to play their characters but allows for some story elements as well. This would be good way for PC's to get legendary items and makes it more in keeping with the story.