My response is: Just say no.
And I quote: "The main difference between the Enlightened scientist and his Tradition counterparts is that he remains completely unaware of his use of magic." That’s fucking amazing. He can use the Awareness talent on his fellow technomancers, but not on himself, I suppose is the point. Mages cannot "abandon" foci until Arete 6, now. But they can spend Willpower and use magick without foci at a higher difficulty regardless of their Arete or the day of the week. Unless they’re Technocrats, in which case they can’t do this, either. This is not so much a weakening of Revised as a failure to improve an absurd situation.
To cross in the Umbra, you now take damage. Everyone’s heard that part. But did you know, the higher your Arete, the more damage you take? Nothing makes it more obvious that the Mage revisors made no effort to think before they made up rules. Why didn’t they just make it a Strength + Occult roll? Furthermore. They’ve implied over and over that the Ascension war is over and magick, by sleeper mandate, is dying out. There’s so much wrong with this, that I’ll just restrict myself to saying that the name for Mage Revised should have been "Sleeper: the Huddling in Listless Ignorance." The abilities list is no better or worse than Mage 2nd ed, just revised. (That is, it’s got equally many glaring gaps in it. Now, there’s nothing remotely like empathy or Lore, for example.) The sphere descriptions are slightly adjusted in places, but nothing that really changes Mage magick. And not much of anything is more clear. Though it didn’t catch my eye at first glance, as someone else pointed out, the Mage Revised book is even less complete for running a game than Mage 2nd ed.
You’d have to be a no-life jackass with nothing to do with his time except criticize game hacks, to buy this book, if you had much of an impression of it beforehand.