It FEELS to me like it's a mix of story seeds, character stuff, crunchy rules bits, and other spurs for the imagination. It may not see total usage in your saga, but it may be some pretty meaty food for thought and inspiration.
So, it seems a fair bit like Ancient Magic in that respect, as opposed to a Magi of Hermes.
There are 2 entries for Thomae's Control Chain, and 2 for his Tender. Obviously I havn't read the book, and maybe that's correct. But it seems more likely a typo. Assuming a typo, can it be fixed before it's sent to the printers, or too late?
I'm not sure about the costs involved, but I think many Ars Magica fans would prefer a straight subscription model like Paizo has for their products. The issue there of course, is that Atlas then competes with its own merchants who sell their stock.
When I first heard about this book at Grand Tribunal last year, I thought it was just going to be a collection of Magi biographies, and thought this might be the very first AM book that I don't buy. But upon reading the TOC, I am very excited. The fact that the Magi have left something behind for Seekers to Seek, and that there are nice 10 page adventures for each (even if not fully fleshed out), well, I will order it as soon as it's available. The more adventures in my library the better!!!
I'd like at this early point to make clear that Ben's griffins in Sub Rosa, and mine in LoH, were developed independently. He and I have this habit of writng the same stuff at the same time, but his tends to come out first. 8)