I've been disappointed for a while with Lackey's books. It seems like, when she decided to team up with her husband, the general quality level of her Valdemar books dropped significantly, and they began to read like YA titles. Very YA titles. And so I drifted away. I'd read the new ones, be a bit ho-hum about them, and wander off to something else.
I really feel like the first two books of the Foundation trilogy are a return to the writing style of the Arrows and Last Herald-Mage titles. They're not quite as grand -- the first books of a series tend to be the best, in my experience, and Lackey has done some significant exploration of the history and world of Velgarth. That she's able to return to some of the simplicity and grandiosity of the first few books really was a very pleasant surprise.
I just want to say, on the off chance that she checks the reviews for these books, that Lackey was really my introduction to epic fantasy as a genre, and it's really been something I've enjoyed for my whole life as a consequence. I was 13 when I started with the Last Herald-Mage, and it's been fifteen years of absolutely amazing adventures, and through her, I've had my eyes gently opened to some of the more pressing issues of our times. I would not feel guilty giving these books to a young adult in the early teenage years, depending on maturity levels, but also feel as though they're written for an adult.
Either way, definitely worth a read. Writing style and story are on the same level as Brightly Burning, though Mags is not as legendary or as outstanding as Lavan Firestorm -- which is not necessarily a bad thing. I hope I don't have to wait two more years to find out where Mags ends up. :)