I don't particularly like the layout, but the contents are... shadowy. In the best possible way. This 5e adaptation to the 3.5 Tome of Magic class captures everything I loved about the original: a complexity, rarity, awkwardness and all that introduction about the philosophy of Shadow Magic is just astonishing. The mechanics can be a little difficult to master from the start, but if you're willing to invest some time with your DM to get it right, I'm sure they'll allow it, as it's not unbalanced in any way (I would even argue the class features sometimes are below the power line). And if you can play it in a campaign, you'll be rewarded to have an interesting character with unique, flavorful and unseen powers.

As a big Eberron fan, I'll start saying that there is no way a new product would disappoint me. That being said, I just learnd from Mike Mearls via Twitter that, as playtest material, this will be updated as it is corrected and enhanced, so now I see it as a one-payment subscription into Eberron's 5e playtest.

I'll be waiting for the definitive Artificer class, but in the meantime my party will have lots of fun trying the new races. I also think that Keith Baker and Ruty Rutenberg show a lot of creativity trying the dragonmarks as sub-races and including Eldritch machines in the Magic Items chapter.

Best thing, though: thius book comes with the announcement that Eberron is now free to create content and publish here, so I expect tons of new content from these great authors.