I didn't find it particularly useful, though as usual, it was still a decent read.
The main things I got from it were the Magical Groups and advanced Metamagic, and some of the magical security and countersecurity tactics.
I didn't really find the grimoire to be that relevant; there's a few useful spells, and most of them are kinda interesting to read, but a lot of them seem "Fancy, but more expensive and less useful than a standard mana/stun/power bolt.".
[3 of 5 Stars!]