Despite a few editorial and design issues initially (which at the time of this review have been fixed) this book is fantastic! I utilize it as an 'additional core' for our Starfinder campaign.
The additional races are better balanced than their Pathfinder equivalent, and the classes are up to snuff with the Core Starfinder classes, adding a bevy of new options and abilities to the table.
Highly recommend picking it up for the price, and I know I intend to try and get my hands on a physical copy or two to have for quick reference!
[5 of 5 Stars!]