Content: Lynn Abbey's Planeswalker has a much darker atmosphere than it's predecessor (the excellent The Brothers' War by Jeff Grubb), but that is because it approaches things from a much different angle. Instead of being an adventure story, it is instead a book on the protagonist's psychological state in dealing with the losses suffered previously through the eyes of his companion. It is a very different and mature book, but that is in no way bad. The writing style is crisp, the characters believable, and the analysis of the emotional states of the legendary figures is perhaps more acute than in any other book in the series. All in all, an excellent read.
Conversely, J. Robert King's Time Streams, perhaps this reviewers second favorite book in the M:TG cannon, starts as an upbeat story about discovery and hope. Then, it rapidly descends into one of nightmares and survival. The great thing about it, though, is that's entertaining the whole way through. We are pulled further from Urza and closer to his companions, but since those companions are amazingly interesting in their own right, the book is actually enhanced by it. The story really shows what an obsession does to the people around the obsessed and how they deal with. A final note: it was able to really give the scope of many years passing, so that by the time I'd finished it, I felt that I'd been with the characters forever.
I'll have to put Lauren Colemen's Bloodlines as the weakest of the three, but it is not a bad book by any stretch of the imagination. As far as the writing, characters, and pacing, the book was great. There are some characters you love to hate (I'm looking at you Gatha), and the romance is actually quite touching. Even the plot was pretty good as we take a look at Urza's preparation in area's away from artifice: eugenics and genetic manipulation. However, the book feels slightly rushed at times and there is a good reason for it. The first four books of the Artifact's cycle were commissioned to describe stories from expansions in the card game that had already come out or were in developement for quite some time. Colemen's book, however, had a very scant gestation period and had to be out the door in time for the expansion it's story coincided with to come out. If only she'd been given a few more months, I think the book would have been better for it.
Presentation: Many will find the omnibus format, with its large books and hefty weight, to be a tad cumbersome. However, as a fan of the 40k series, whose books are repackaged into omnibi (omnibuses?) regularly, it wasn't really that difficult or unfamiliar. That being said, being able to get three good books for a discount price was great, especially because those books are hard to find at your local bookstore.
So, if you are on the fence about this book, I'd definitely recommend it. Whether you're a old fan or a new reader, it's a great value you shouldn't pass up.