Physically, it's a very nice book. It's big. Almost too big... but not quite. The art is not my preferred style, but it is a pleasing style. I enjoy comic book style fantasy art and the PF stuff is very similar.
The "combat maneuver defense bonus" or whatever it's called is both a concept and a name that could only have come about in a later edition of a game. What a lumpy little monster! However, it is much more elegant and balanced than the numerous subsystems it replaced. It is, in other words, good, although it might give a novice indigestion. That is an example of a general refinement.
Gnomes are definitely not elves or dwarves. They are not exactly how I would conceive a gnome, but they occupy their own niche and have their own character apart from the other races. I consider that good design.
The classes... paladins can now heal themselves in a non-futile fashion. Fighters have a 5th level ability, plus they have Survival. Rangers killed the Horizon Walker and Scout and took their stuff. Sorcerer bloodlines replace but do not replicate bloodline feats, and give an easy tool to flavor sorcery in a given region or campaign (plus, the Destiny source is something different from the norm, and helps give the feeling of a world where oaths and destinies and wishes can shape reality). Turning animal companions into a building system rather than tacking on monster advancement rules is not only good design, but almost exactly how I would done it (I personally would have reduced animal companion to a single set of characteristics, then handed out ability score modifiers, senses, natural weapons, armor, and movement to the various choices). Barbarian rage powers are much improved over the beta version and some systems I've seen, and I think add some customization options that are worth having. Wizards who are generalists no longer get passed over in the firepower department, while specializes are no longer crippled when it comes to providing a variety of spells.
I am happy that despite a lot of changes "under the hood," most things work basically the same. For instances, the Prestige Classes from Love & War are probably underpowered now, but workable. I can rebuild them easily enough. However, almost all of the feats are usable as-is. That is great.