+1 for Boom
That's where my Boom resides, garage, wall mounted, streaming 24/7.
Audibly fills the space nicely. Plus you are already familiar with it's interface.

But a Radio wouldn't be a bad choice either.
Take away the alarm issues and the many (understandable) complaints from EU MySB users and this Radio forum would be as dead as the Boom forum.
The US MySB is quite a bit more reliable and I use it regularly with Radio & Boom.