I'm a DM, so my books are going to be DM-focused rather than player crunch focused. And if you're going to DM 5e, the only resource you should need is a solid adventure (well, maybe monster stats).
Best: "Lost Mine of Phandelver"
A brilliant intro to 5e, which I've run 3-4 times. Great sandbox to explore with room to expand. Nothing too wild - presents a "core" D&D fantasy experience with goblins, dragons, undead, and big treasure.
Worst: "Horde of the Dragon Queen"
Railroad adventure on a literal caravan. Imbalanced encounters. Massive leaps in logic to get to where the group needs to go. A travel log of the FR, without enough detail to present the FR. No time to actually enjoy the scenery, because you're whisked away to another location immediately.