Bought it. Haven't "used" it. **Spoilers**
Sir Osis of Liver said:
For one the Prestige race thing is wicked cool.
The pc races are nice, for the most part.
The overall concept is interesting to me too.
I also liked most of the art.
I also really dig the prestige races concept. Definitely my favorite part of the book. The next Dragon Mag will feature prestige races from the blurb I saw in the current one. Hopefully it will be something different from what is in Oathbound. ( I believe the Dragon article is being done by Brannon H, an Oathbound contributor )
I'm still... learning to appreciate Todd Morasch's art.
Spoilers alert....
I have to admit that I was hoping that the Feathered Fowl (FF)would be more prominantly featured, their abodes, minions and machinations etc...
The whole reason the FF bring PC's & other creatures to the domains is that they are hoping to be killed by the PC's and released from their duty/imprisonment. Each domain holds a key to a dark god's prison that the FF must protect unless/until someone more powerful than them takes their place.
But nobody knows this, and they can't tell anybody. And there is really no way to find this out. But even if the PC's did want to kill one...
There does not seem to be any way to permanently defeat one. The one FF with stats in the book has an "Avatar" that is CR 30 ( and other deity SA's ), that will, of course, reform unless the "real body" can be found.
And, oh yeah: each citadel of the FF is protected by a miles & miles long pathway ( yes - the only way in ) featuring HUNDREDS of Golems with DR 40/+3.
Ok - so what kind of motivation will it take for your PC's to come up with the the idea to take on a FF? I can't imagine. Maybe Bastion will produce an Epic Module with some loopholes sometime in the future.
So - what are the PC's to do once they are here? ( The book focuses heavily on the political machinations of various factions in the city of Penance)
Maybe I'm missing the whole point of Oathbound, as a neat new place to explore, but as a DM, I'm having problems conceptualizing PC motivations for adventuring.
What I really like about Planescape ( which Oathbound is often compared to ) was that PC's adventured into the planes as means to an end. They travelled to different places for a purpose.
Although I never ran or played a game in the setting, I imagine Oathbound being more similar in concept ( with less undead

)
to Ravenloft than anything else.
Whew. I'm getting wordy here...
Any Oathbound journeymen here wanna offer some motivations/plot hooks etc.. for those of us who have it but are not using it, or for those considering buying it?
edit: a glaring spelling error or two