The Beam is designed for "Small to Medium" sized rooms. Roughly what size is meant?
Best answer by Stanley_4
Room sizes are discussed here a bit, try the search until someone gets back to you on it here.
As far as normal use, a controller (desktop or mobile app) will control either or both systems. You can pick one or the other using the Rooms option on the controller or from the same location you can group them so they play the same music in sync with each other. You should be able to play the line-in on the connect using the Beam.