This is a solid book full of fun new character options and useful material for GMs that reinforces all of 5th edition's strong points.
The new subclasses are well designed and flavorful, with some of the most interesting new abilities not being focused on combat. GMs may detect a little power creep here and there (is there a reason to choose College of Valor now that College of Swords exists?), but play will tell.
The character life-path tables are fun, but their usefulness will depend on how much character background you want to leave to chance. As a tool for inspiration, however, they could be very useful.
Likewise with the random encounter tables. Some GMs will get more use out of them than others, but they're a nice option to have. Unfortunately, they do not seem to include any of the monsters from Volo's Guide to Monsters. A strange oversight.
Many of the new options originally appeared in Unearthed Arcana, and most do not seem to have been significantly altered. It's nice to see these things have an official release, but it still leaves the reader with the feeling of having seen these things before.
The worst part of the book is the last several pages dedicated to tables of random names. I understand the thought process behind including it, but mostly it seems like a way to inflate the page count to justify the $50 recommended price tag. At $30, though, it's only a mild gripe. Minus one star for the filler.
Unrelated to the book itself, Amazon's packaged for this item was abysmal. It was sent in a box too large for it with nothing but a single sheet of air bubble wrap tossed on top of the book to "protect" it. Unsurprisingly, my copy arrived damaged. I guess Amazon has reached the point where they are so dominant that they no longer have to care about the quality of their work. Amazon's completely inadequate packaging job did not affect my rating of the product itself.