Not a great batch, frankly.
PHB3 suffers, I think, from following the exceptional PHB2. It does add Superior Implements and Skill Powers, which are both excellent. The classes, though...
* The monk is exceptional
* The seeker and Runepriest proved to be unpopular
* the core psionic mechanic is interesting, but it was executed poorly. All three classes have level 1 at-wills that they should continue to use all the way through level 30. Considering that a ton of space went into publishing at-wills that are supposed to be acceptable replacements, this was a disaster.
The races were somewhat mediocre in my mind as well. The minotaur has great flavor, but the core reliance on charge limits its appeal.
Martial Power 2 was full of interesting ideas, but simply not as useful as martial power 1. That's to be expected, I suppose.
PHB Races was a dud because of the extremely narrow focus. Put out a race book covering each of the PHB1 races in detail and you'd probably have a hit on your hands.