Got the printed version. It is a nice and fast look up option, and a good addition to the game. Today many of the contents are reprinted in other official books, but if you don't want to spend a lot of money just to get this specific content I can highly recomment it :D

Technically the first dedicated official rules expansion for D&D 5th Edition. It's short, but it does have four neat race write-ups and a selection of neat new elemental spells. Very good stuff, just unfortunately brief...

While you can find a lot of this information in other products, it's a nice quick guide if you know what you're looking for is in here. Also you can't really beat a free PDF, y'know?

While this is available as a free PDF on Wizards' website, I decided to order the print edition once I saw it was available again on the DMs Guild, purely for the novelty of owning a physical copy to pull out at the table. I kind of wish these sorts of releases had become a more common part of the 5E release scheme, but I understand why they didn't. It's a cool supplement, however. While genasi got published in the Princes of the Apocalypse hardcover and deep gnomes are all over the place, notably in the Sword Coast Adventurer's Guide and goliaths are in Volo's Guide to Monsters, I do believe this is still the only place you can find aarakocra as a player race. The new spells are also all in Xanathar's Guide to Everything. So for the most part this book could be seen as wholly unnecessary, it's a neat option for anyone who doesn't feel like looking for those other sources, or like me just wants to collect everything from 5E that Wizards has put out. That said, I will note that while it was thought the whole reason this was taken off the DMs Guild was to incorporate errata into the print edition, this print copy is still the "March 2015" printing and NOT the updated November 2017 edition. Your mileage may vary on how much this bothers you, but it certainly feels like an oversight.