Great source of new options for your PCs. I bought it largely so my group had more class options when leveling up. Nanos get a lot of buffs. Glaives get a few abilities to round them out. And Jacks get a lot of love with stuff that makes them more unique to play. And that's not to mention the new descriptors and foci that add a lot of cool options.
If looking for a negative point to make I'd say the new races don't inspire me a ton (so far my favorite has been Artificially Intelligent from the Tech Compendium) and a few of the foci are limited to a themed campaign (like the ones focused on fighting automatons and mutants or the various underwater/sea-based descriptors). But then again maybe for another player those would be just what they want and there's more than enough here to satisfy me, especially for $10.
[5 of 5 Stars!]