Not sure if people are aware, but it is possible to get a YouTube channel on their Roku - I've only just discovered it myself.
There is a side-loadable ZIP file available here that allows you to load an "un-official" YouTube channel to your Roku.
As it is side-loadable, it can also be added to the Now TV box, but it will overwrite any other side-loaded app already installed, such as the MB3 Roku app.
I have it installed onto my daughter's Roku 2XS and she uses it to watch "MineCraft" videos.
She has watched a lot of these videos and hasn't complained once about any problems, so it is fairly stable.
More information can be found here.