I would likely go with a Beam in that situation, as it was built for room such as this. Probably used the money saved to add surround speakers.  However, if you’re wanting to get the atmos audio, or expand to a larger room at some point, then it’s not a bad idea to get an Arc with that in mind.  Then again, if you expand later, you could just the Arc then.  No real wrong answer here.

Thanks Danny, leaving aside the obvious desirability of Atmos, I was just wondering if the Beam, in a small room, performs near enough as good as an Arc, as the Arc would not have the environment to shine.

I guess I am asking , is the Beam really as good as the reviews would have you believe?

Thanks for the input. 

Anyone else have a viewpoint to help out this Sonos Newbie?

What are you primarily using it for? Streaming movies, watching Blu-rays, or gaming?

Mostly films, a little TV and gaming

Do you watch movies on Blu-rays or primarily stream movies? If you watch Blu-ray or UHD discs, I recommend the Sonos Arc with the HDFury Arcana device that would allow you to bypass your TV’s HDMI ARC limitations and get lossless Dolby TrueHD/Atmos and multichannel PCM audio (from DTS discs) from all of your discs which sounds FANTASTIC from the Arc. But if you are only streaming movies, I would just stick to the Beam and use the extra cash to add a Sub or two One SLs as surround speakers.