I skimmed it at my FLGS on Monday, and it looks great. Definitely on my "buy" list -- and if you don't have the associated creature book, Monsters of the Mind, you should run out and buy it. It rocks, and it's great as a standalone. I can't wait to actually pick up Mindshadows.
It's an interesting setting. There are also some crunchy bits, but they aren't what makes the setting cool.
Psionics is adapted well in the setting. Think Buddhism... very cool...
Yuan-Ti... 'nuff said...
Interesting political and religious history... this part is well done.
Nice twists on the standard PHB races. The only race that wasn't included was Half-Orc (as there are no Orcs in the setting). Heck... I think you would be hard pressed to find a Half-Elf in the setting, though it is possible.
Juggernauts... Basically magical mecha... This is the one part that you will either love or hate. We weren't quite sure what to make of it while playtesting because it was hard to imagine what these things might look like. The illustrations in the published book help somewhat, but I'm still not sure if I like them.
Oh yeah... I'm working on a Mindshadows/Arcana Unearthed conversion. My group actually played it, but it was a bit cumbersome mixing AU magic and races with Psionics...
I don't see why you couldn't do this. All you have to do is treat the various PHB races as different cultures within the setting. The only one that might take a little effort is the Dwarves.
I have it. It's very well written, and I like a lot of the ideas in it. That said, I am not to fond of classes without a unique spell/power list that have their own progression. Fortunately, James Malizewski reports that they are going to make "manifester level" versions of the classes on their website.