As for what's inside, you get a 4th-gen 1.4 GHz Intel Celeron 2955U processor, 2GB of memory, integrated Intel HD graphics, and a 16GB M.2 solid-state drive for storage. The system boots in less than 20 seconds, and the combo is powerful enough to efficiently run Chrome and Web apps. Streaming HD video from Hulu Plus or listening to Spotify or Google Play Music while working in other tabs didn't pose any problems, and even under heavy load it stays quiet.
If you're the type to have a couple of dozen tabs going at once, you may want to consider the $370 Intel Core i3 version, which also doubles the RAM and bumps the integrated graphics up to an Intel HD Graphics 4400 chip that can support display resolutions up to 4K. There is a Core i7 version, but that appears to be for Chrome for Meetings only.
Storage space remains 16GB regardless of the model, though. It does support external storage drives, and there's a memory card slot. Two years' use of 100GB on Google Drive storage are included as well, which makes sense, given the cloud-computing nature of the product. And this is a desktop, so you're more likely to always have an Internet connection than with a Chromebook. For doing that, there is dual-band 802.11n Wi-Fi and Gigabit Ethernet.
All in all, the Asus Chromebox does what it's supposed to do, does it well, and looks good doing it. But the key question, as always, is whether what it can do is enough for what you need to do.
The easiest way to figure out if either a Chromebox or Chromebook will meet your needs is to install the Chrome browser on your current computer. If you can accomplish everything you need to do on a daily basis, then there's a good chance that you can get by with a device running Chrome OS as a secondary or even your only computer.
This might mean switching from Microsoft Office to Office Online or Google Drive, or dumping Apple iTunes for Google Play, which, depending on your comfort level learning new things, could take some adjustment. (Chrome does have a free secure Remote Desktop app, so you can help a new user through a tough spot if you're considering this for someone who's less tech savvy.)
Google lists out some common app replacements for desktop software, but you can also search the Chrome Web Store to find solutions. There are Web apps that work offline and outside of the browser, too, and, again, anything that runs in the Chrome browser will work on this box.
For home use, a Chromebox makes a nice family computer. Though you'll likely still need a Windows, Mac, or Linux computer to do some things, the security features and the capability to easily set up and manage supervised users is certainly nice to have.
As for business and enterprise use, I can't really say much beyond that a Chromebox looks like a promising solution. Chromebooks and Chromeboxes can basically be used as thin clients, thanks to a VMWare partnership and a new Google Admin console simplifies management. And just as you can limit what your kids have access to, you can limit what apps employees can install or use, and what sites are accessible.
The Chrome OS has come a long way since it showed up in 2011, and the devices running it have improved quite a bit as well. The Asus Chromebox shows off what the platform can do at an affordable price.