This is a fantastic alternate setting and especially for AGE games (although the Pathfinder roots remain quite evident and are sometimes jarring). It is well organized and beautifully illustrated. Even if one only intends to mine the sourcebook for piecing into a homebrew campaign the backgrounds will be extremely useful both as written and for inspiration.
This is not Earth restyled. Midgard is flat and has a rich cosmology. Included are not just sections on the divine but descriptions of festivals, holidays, and languages. A rather nicely developed urban area named The Free City of Zobek is provided but there are also non-standard areas such as kingdoms of vampires and ghouls. Nor are all the races stock fantasy in origins as Midgard features some distinct takes on such matters including the nomadic Windrunner Elves of the steppes. Adventure seeds are provided and culturally specific weapons and equipment detailed.
In fact, I have only one real complaint but in my mind it is a major problem. The PDF has no print-friendly settings. The illustrations and decoration is quite nice but printing the document (even inpart) will be prohibitively expensive. I gues some could order a bound edition rather than the PDF but the electronic version makes it easier to design adventures and customize the game experience.
Open Design is to be commended for a very strong offering but the lack of a print friendly layer or discrete download knocks it down a star. Buy this PDF only if you never intend to print most of it OR you are independently wealthy so that printing costs won't bankrupt you,
[4 of 5 Stars!]