A lot of useful stuff here; 176 pages is pretty hefty, and even the fluffy sections - like the brief descriptions of different nations - have some suggestions on how to tailor the game mechanics to fit the world. The new races seem a bit cumbersome - too many abilities - on the first read, but I'm interested to see how they feel in play. Definitely worth buying if you want to bring Eberron into your 5e game, especially if they keep updating and adding to it. Need that artificer!
Only 4/5 cause $20 feels like a bit much for a playtest document, but hopefully will pay off over time.
[4 of 5 Stars!]