All current models of the Roku are supported. You can find out what those are at the Roku.COM website. If you plan on using the Roku with an older TV which does not have HDMI, you will need the Roku Express+ model, which has analog A/V outputs.
All the current Roku devices will work with the Xfinity On Campus channel app. The Streaming Stick has a faster UI, and better wireless (2.4 and 5 GHz) than the base model Roku Express.
Registration instructions can be found at the Xfinity On Campus website once you log in there. A shortcut set of instructions may be found at Using a Roku Device with the Xfinity on Campus Service
Roku will ask for a payment method. There is no charge associated with using the Roku for Xfinity On Campus, so unless you're planning on using purchased apps, you can select `Skip' for the payment method.
The Xfinity On Campus service only permits one stream at a time per user. If you end streaming on one device, it can take a minute or two before streaming will be available at another devices under the same account.
Access to Xfinity On Campus is limited to students residing on campus, while connected to the MIT network.