Well, it's been out for about two weeks now (for us lucky ones who managed to get a copy at Gen Con).
They've definitely learned a lot of lessons from earlier Mage, some of the big (and welcome) changes:
1. The first dot of a type of magic (Arcanum now, Spheres before) is a lot more useful than it used to be. Instead of just purely sensing, you can do some limited manipulation with the first dot.
2. It's easier to create a starting mage with any real power level, since Gnosis (formerly Arete) 1 lets you get up to 3 dots in an arcana. You also start with 2 dots in two arcanum and 1 in a third, meaning even a basic mage can cast spells that really affect things without buying up their arete gnosis.
3. Becoming a stronger mage actually makes it easier to draw Paradox, power has it's price. The overall theme of new Mage appears to be "With Great Power comes Great Responsibility".
4. They made mages a lot more rote dependent, you can still try and improvise spells, but rotes work an a whole lot better. Probably for crossover balance, since Mages are quite flexible with what they can do.
5. They really spelled out the cosmology nice and clearly. The descriptions of the old Umbra were clear as mud. It is harder to visit than it used to be (no weird Avatar Storm at least), and the the game is clearly based on Earth, but if you must venture across the Abyss or the Gauntlet, the game at least makes it clear enough what is out there, and how it all fits together.
6. There are actually rules (guidelines more) for the 6th dot in an Arcanum. Not much more than saying it's a plot device-level, but at least they acknowledged it instead of consigning it to an obscure and overpowered splatbook. They also had powers capping out at 6, and those are hard to get.
7. Liches, they have liches. I like that Tremere are now Mages who have to devour the souls of others.
8. The 5 "path" splats are pretty broad, although saying that 2 of your 3 starting Arcana have to be the 2 Ruling Arcana of your splat is a little limiting.
9. The focus is definitely back on being a Mage. It's clear that mages are supposed to cast spells, wave wands, perform strange rituals and the like. Weird arcane hackers, mad scientists, raver kids, men in black and the like aren't impossible, but the game makes it clear that they aren't the norm.
10. No Technocracy. I thought they were kinda cool, but not having Them as an everpresent opponent really can make the game more about roleplaying, and less about matrix-esque gunfights and blowing up Space Marines (which is what a lot of Mage games came down to).
11. The default setting of Boston/New England seems quite appropriate. Cold, dark New England villages with a distinct Lovecraftian and/or Stephen King feeling seem quite appropriate for White Wolf mages (not to mention the obvious Salem).
12. Style. Mage books always were colorfully written and quite evocative of a mood, and this one definitely holds up to that tradition. It's a physically very beautiful book and the book itself seems almost like a piece of art. The "Atlantis" theme for the ancient history of Mages and the chevron look of the "A" in their logo makes me think of Stargate: Atlantis though.
13. I liked how sleeper witnesses to Vulgar magic works now. Sleepers witnessing somebody flying are to rationalize away whatever they saw (much like Werewolf delerium lunacy), and have a chance of making any vulgar spell they witness in progress just fail.
