Between this book and Celestial Chorus, it feels like Mage is self-consciously entering a new phase of its existence. Both are aggressively inclusive, attempting to cast their respective Traditions as players on a global stage. But whereas Celestial Chorus felt like it was encouraging diversity at the expense of ignoring some important cultural context, Cult of Ecstasy feels much more natural when it draws from a multitude of different societies.
Now, fair warning, this impression may just be because I'm less familiar with Cult of Ecstasy's subject matter. When the book talks about Erzulie worshipers or the Vratyas' Tantric practices, it could just be a case of the careless appropriation of sacred things only vaguely reminiscent of the book's whole shtick. In fact, it actually seems pretty likely that Cult of Ecstasy is about as faithful to real-world ecstatic mysticism as Celestial Chorus was to Christian theology (i.e. not much at all, but at least within sighting distance of some familiar concepts). I'm just saying that a group defined by a shared interest in seeking transcendence through overwhelming their physical senses feels more natural than the idea that a bunch of competing monotheists will put aside their differences and agree on a universalist syncretism.
It's entirely possible that this book is offensive as hell and I'm just too clueless to get it, but acting on the assumption that it's not, I have to say it's mostly . . . hwuh? It makes a decent argument for the inclusion of the Cult of Ecstasy as a Tradition, but it also quickly butts up against a big problem with Mage as a system - all of the Traditions have access to all of the Spheres.
Ultimately, the reason this is a "problem," is that the Cult of Ecstasy really wants to have access to techniques no other Tradition can match. "We scour away our conscious minds so that our spirits may touch a deeper cosmic awareness" is a tough pitch when the punchline is "as a Time 2 effect." What the Cult brings to the Traditions is their skill as seers. But anyone can be a seer.
(The flip side of this is that Cultist can also easily do things that are out of genre like telekinesis or turning lead into gold. Players are expected to police themselves to stop this from happening).
I don't actually have an elegant solution here. I bring it up because there was something jarring about reading so much about their extreme methods and then realizing that there's no reason they need to be that way. But, of course, the same is true for basically every Tradition, when you think about it.
I'm also not entirely comfortable with the way the book handles all the sex stuff. It is very clear about the importance of consent, but it makes the (frankly creepy) decision to point out on multiple occasions that nonconsensual sex magic works, but that the Cult forbids it on ethical grounds. I can see a plot point there, but ugh, I don't want to take even one more step down that road than I have to. Just, no.
Also, mentors are expected to have a sexual relationship with their students. And I guess it would be weird if you didn't have sex with the person who was teaching you sex magic. Just on a practical level, maybe that's how you learn. But the book barely even touches on how huge the potential for exploitation is.
Call me a cynic if you must, but I don't find "we've just described a perfect recipe for massive institutional abuse, but don't worry because the people involved are too spiritually enlightened to do it" to be especially reassuring.
It does feel, however, that Mage supplements are getting consistently better as time goes on. This book definitely feels more researched than any of the ones that came before, even if I suspect that it doesn't quite understand the underlying spiritual logic of the practices it describes (for example, it includes the Aghoris as a semi-renegade Cult of Ecstasy faction, and after looking them up online I suspect that their depiction here was based off hostile sources - as near as I can tell, they're an apt inclusion, but their particular brand of heresy is closer to trolling than it is to the wickedness this book describes).
Ukss Contribution: I was going to pick the Aghoris until I learned that they were real people that the book misrepresented. My next choice was Jim Morrison, who is canonically a member of the Tradition and probably still alive in the mage universe, but I don't want the hassle of dealing with a real person, especially one who lived so recently.
I think I may just have to go with the Cult of Ecstasy as a whole. Ukss already has an organized group of seers with a hippy vibe and utopian goals, but I figure that maybe the Lunar College of Prophets could use a rival organization, one which embraces chaos both as a methodology and an end in itself.