I think the book is excellent.
First of all, about Rune feats: Not only do they lack normal pre reqs, but they're also the bonus feats for the Rune priest class. Obviously, as a fighter cleric hybrid, they shouldn't have the same quality/quantity of bonus feats as a fighter. However, they get the rune feats, which are similar, but have some minor restrictions so they aren't as good as real bonus feats. And there's not as much bother about prereqs, which they'd normally have a hard time with. I think they work well for the characters that were meant to use them.
However, I think there may be some minor flaws. The slayer section seems to incorrectly imply that favored enemy gives a to hit bonus (pg 45, role in the adventuring party). Also, it appears as if the 10th Tunnel Slayer level is imcomplete. After the one wall tunnel fighting, there is a comma and an extra row in the table, leading one to believe that there's a missing ability. Note that the existing sneak attack progression would suggest another bonus die at level 10. Perhaps that's the missing ability.
The feats, prestige classes and fighting styles seem well done and balanced.
Probably the main "problem" with the prestige classes is that none of them really strikes me as an amazing idea to set fire to the imagination. There's nothing like the Forsaker, which, despite its problems, turns a valid and interesting concept from a fast track to a new character to a decent character. They seem solid, but not inspired.
Overall, I'd probably say that there's as much quality stuff in the $10 HoHF: Dwarves as there is in the $20 WotC splatbooks.