I'm getting really excited for the arrival of Revised edition. Orphan's Survival Guide was like a proto-Revised. Guide to the Technocracy was Revised-compatible. And Initiates of the Art feels a lot like a Revised book that's arrived just a little bit early. If it weren't for the lack of the weird, busy page-borders, I'm not sure I'd have been able to guess that it's technically second edition.
Unfortunately, while Initiates of the Art is a decent enough book on the merits, it suffers from Revised edition's greatest weakness - an often regrettable reluctance to include overt fantasy elements in their urban fantasy game. Magic is covert, shrouded in coincidence, because it is dangerous to be too blatant with your spells, but that can unfortunately translate into a magical world that looks quite a bit like our own.
I need to tread carefully, because I don't want to overstate the case. I actually really enjoy Revised's "magic exists in the cracks of the mundane world" approach, and it would be wrong to say it never went all-out in painting those cracks with bold, bright colors to contrast the grey. However, it would be accurate to say that they don't do it here. (And I know, I know, this isn't technically a Revised book, but it really feels like one).
The problem, I think, is two-fold. First, this depiction of life as an apprentice is not nearly sensual enough. People become apprentice mages because they've seen impossible shit and now they want to do impossible shit. But for all it talks about maintaining relationships and holding down a job (useful, character-building stuff, mind you), it never captures the awe of awakening to a magical world. When it talks about magic at all, it's in a very cerebral way - it's interesting, but it runs the risk of making magic seem like something you do to win arguments with other mages, rather than something that gives you amazing superpowers.
Although, to be fair, part of the reason it's like that is because it's more or less forced to be by the Mage rules. The only thing you can do with the first rank of a Sphere is sensory magic. Now, don't get me wrong, I'd love to have the ability to see in the dark, read auras, or determine how much charge is left in a battery by smelling it, but for all the utility these 1-dot spells may have in my day-to-day life, in the context of an rpg, they don't necessarily feel like my character is taking the first step on a path of miracles.
They're doing the best with what they've got, but I'm left with the feeling that maybe someone who's an apprentice relative to a sorcerer can still be a jaw-dropping badass compared to an ordinary slob like me. At the very least, give the apprentices 2 dots in their spheres, so they can occasionally have a tangible effect on the physical world.
Although, it's actually questionable how much of the blame for this I should put on Initiates of the Art. At its heart, the problem is that Mage: the Ascension is completely broken at Arete level 1. It has been since the first edition core and it continues to be up through the 20th anniversary edition. I might find fault with this book for encouraging this mode of play, but honestly the character creation chapters of every Mage core include rules that charge you points for making a character that's not completely miserable to play. They don't even have the decency of telling you that you must spend those points, as a kind of character-creation tax, if you want the game to be even minimally functional (though Revised does seem to suggest that it's expected, whereas 2nd "recommends that you raise it no higher than 3," M20 implies that you're cheating yourself out of the fun of the early game if you do it too often, and 1st edition is pretty neutral).
It's important to note, that when I say Mage is "broken" at Arete 1, I don't mean that it's too low in power level for me to enjoy. That's just a matter of opinion. Everyone has their own preferences there. No, what I mean is that mechanics of the Storyteller system break down and your attempts to use magic will become a cruel farce. Basically, the system is not set up for you to roll a single die for anything, let alone your character's main shtick. And the magic system in particular will punish you for trying.
For example, if you are trying to see in the dark for the rest of the scene (a completely reasonable use of your powers that should probably just be a passive ability), you need to roll 3 successes. With only one die, you'll need to make it an extended roll. The difficulty is 4, which means the chance of doing it in 3 rolls is 34% The chance of botching in that same time frame is 27%. The likeliest outcome is doing it in 4 rolls, with a 2/3 chance of success and a 1/3 chance of botching (that these numbers add up to 1 is a coincidence, though if you fail all 4 rolls, your chance of rolling at least one botch is 81%). The reason for this is that with one die, you botch every time you roll a 1, and the number of permutations that does not contain at least one "1" shrinks fairly rapidly. After 7 rolls, you are more likely to botch than not, regardless of what the original target number is. Starting at 4 successes, you are generally more likely to botch than you are to succeed.
That's to say nothing of the action economy in combat, or the pointless tedium of open-ended repeat rolling in more sedate scenes. It's just a complete clusterfuck.
My mathematical intuition tells me that if you want the game to work more or less as the fiction suggests it should, apprentices should roll approximately 4 dice for spells. The idea for an apprentice game is a good one, and Initiates of the Art gives you a lot of good ideas, despite its system limitations, but if you want it to actually feel like you're playing novice sorcerers, Arete 4, Rank-2 Spheres is my suggested minimum power level.
Before I wrap up, I also want to point out a bit of shifting canon - Avatars (the mysterious oversouls that let you do magic) are discussed here as directly as we've seen so far. Established facts - everyone has an Avatar, but most are too weak to do magic; who gets the strong Avatars seems random, or at least subject to the inscrutable whims of reincarnation ("the Awakening is as likely to strike an otherwise normal person as to empower some occult fantasy mysticist"); it is possible to destroy your own Avatar accidentally, by misusing magic (but no mechanics for such are given).
I can't say I like this new canon all that much. If you can't earn an Awakened avatar, and especially if the wise elder mages can't teach you how to find one, it kind of diminishes the religious themes of the game. I mean, it's not necessarily the case that various religions believe you can achieve enlightenment through your own effort, but it's a little weird for, say, prospective Celestial Choristers to not have to believe in God, or for the long, formal training of groups like the Order of Hermes or the Akashic Brotherhood to have no effect. The game is about finding a path and pursuing it, and while I think it's reasonable for the vast majority to fall off the path before achieving enlightenment, it's also highly weird that those who succeed seem to do so mostly by chance.
I'm just going to file that under "White Wolf's strangely aristocratic approach to supernaturals" and subsequently ignore it for my personal games.
Ukss Contribution: This is a tough one, because it's mostly about cool fantasy stuff being just out of reach. The masters are gone, no one trains in a Horizon Realm any more, and the most impressive of the suggested rotes makes it so you can stay awake all night.
However, it does talk briefly about the idea of Sanctums - areas so affected by the resonance of your magic that your spells no longer cause paradox. In keeping with the overly-cerebral nature of the text, it fails to describe all the jaw-dropping shit you're sure to see in a basement or garage where the Earth's natural laws are held in abeyance, but that's something I can fill in on my own.