I had a look. It's pretty cool, if you like 3.5 you'll love it.
Production values are high, lots of nice art and veering away from the ridiculous style favoured by the 4th edition stuff- comparing the magic items especially is telling.
Most racial stuff is the same, though background for Gnomes has changed a fair bit, everyone gets another +2 to a stat (humans and half breeds pick one).
Class wise, Cleric and Paladin undead turning has been simplified into a burst of damaging/healing energy. Paladins got a serious boost, smiting now acts like a tag on an enemy- every attack is a smite, and the bonuses (which are hefty) double against evil outsiders, undead and evil dragons. Also, paladins no longer need wisdom, everything keys off charisma.
Fighter got a major overhaul, now gets something cool every level, everyone gets more feats. Druid got toned down a bit, which is good, but also got more fun I think (you can turn into a tyrannosaurus a few levels earlier

) Sorceror got a big overhaul aswell, now you pick from a laaaaarge range of power sources and this determines your progression. It's actually very cool and makes me want to play a sorceror. Wizard school choice is kinda similar to that. Rogues are similar but get a few more fun tricks. Hit dice for low down classes went up a bit (wizards are
d6, bards
d8 etc) and every class gets an awesome capstone ability at level 20 that makes it more worthwhile to go the whole way up.
There are a lot of feats, lots more than core 3.5, and lots of spells. The
GM section seems pretty much the same. Oh, grappling and other manouvers have been simplified but I didn't read how.
Hmmm anything else...
Wide selection of magic items...
If I think of anything else I'll post. I've moved to 4th and don't mind it, but Pathfinder is an excellent product if 4th isn't your thing but the holes in 3.5 were annoying you.