I took the original post to imply nothing about hardware requirements. Yes, it comes with a Motorola MS100AN. It's aesthetically similar to an SB6141/6121, but quite a bit larger...almost as big as the MOR200BN HD-DVR connected to my TV.
On the back it has a USB port, ethernet port, SD card slot, cable card, RF connector, reset pinhole and DC power port. The power brick what you'd expect for a device of that size.
It is basically a QAM tuner like any other STB for your TV, except it transcodes the content into H.264/AAC, then creates an HTTP .m3u streaming playlist (re-encrypted of course, so you can't just use VLC or Windows Media Player as clients.)
The SD card slot and USB port are likely deactivated, but I haven't tested it for myself. Once connected, the device has a web-interface accessible on your local network...it makes references to dual-tuner functionality, but as it stands there is only one usable tuner. You can also only use one smartphone/tablet to view content at a time.
Using the XFINITY AnyPlayer app, occasionally I will find it unable to tune into the device until I logout of the app and log back in with my Comcast ID.
The web diagnostics page allows you to reboot the device and check for upgrades. You can even change channels, enable SAP, etc. from the web interface. It also has some rudimentary logging and detailed diagnostics/hardware status reports.
Basically the current AnyPlay hardware is a proof of concept. It's very limited for anyone who isn't single. One tuner, one player device only. Hopefully the new Moto/Arris box with its 8 QAM tuners and integrated everything will expand streaming support to 3-4 IP streams at a time.
EDIT: I also had @ComcastMichael provision/activate the hardware for me. The late-night support reps were completely oblivious to its existence and kept asking me if there was an error message on my TV. I think I told them 20x that the device cannot physically connect to a TV, but they kept asking anyway. If you need the device activated, go through Twitter, ComcastDirect or maybe try the sales department. Once the device is activated, it might take a couple of hours before you can actually tune into the device via the software player.