Sonos is no newcomer to the soundbar space, and the Sonos Beam isn't the new flagship of the range. Indeed, at $599, it's actually a more affordable Sonos soundbar than existing playbase or playbar soundbars.
The Sonos Beam has five onboard digital amplifiers, four woofers and a single central tweeter to handle its audio output. Audio is generally very good, although it's not the loudest soundbar I've hit, and there are some limitations depending on connectivity. Dolby Atmos is notably absent if that's important to you. Soundbars are never going to challenge a proper set of stereo speakers, and I quickly gave up integrating the Sonos Beam into my existing set-up. Sonos does sell a subwoofer product, and naturally you can engage other Sonos speakers to act as surrounds, although that quickly gets expensive if you don't already own them.
Sonos' background is in music, for which the Sonos Beam delivers a strong room filling presence. Through the Sonos app it has support for a wide variety of music sources, excluding Bluetooth pairing with a mobile device.
Testing with the remaster of Prince's Purple Rain gave every screamed note and guitar reverberation their proper purple majesty. There's something to be said for simply stopping and listening to an album properly, a luxury so many of us skip for background music, but then the Sonos Beam has to do a little more than that.
For TV-based audio, the Sonos Beam delivers good central sound, albeit not quite full surround sound for rather obvious reasons. The Sound Enhancement feature emphasises voice nicely, with both quieter dramas and more rambunctious action content mixing in vocals and explosions, while avoiding the whole hassle of punching volume up and down continuously through a movie. Sonos' "night mode" works much like competing offerings, with lower tones to avoid disturbing your fellow dwellers, although you'll still need to keep the volume down.

Digital Assistant performance
Amazon's Alexa is the only digital assistant currently enabled for the Sonos Beam, although Sonos did warn me that I was testing with a "beta" version of its Beam software.
That does give it a slight escape clause in that future software releases may improve functionality, and I'd certainly hope that will be the case.
Alexa is fine as a basic smart home assistant in much the same way that it is on any of Amazon's Echo speakers. Although, like the Sonos One, you do lose the calling ability, as well as spoken Audible audiobooks on the Sonos Beam.
What you should also be able to do is perform simple TV functions when connected via HDMI-ARC to your TV, including volume and power adjustments. My own testing experiences with this were rather patchy, to say the least.
Volume adjustment worked fine, although I suspect most users will work out the one or two levels they always want the volume to be at. The Sonos Beam's five far field microphones work well across the room, except if you tell Alexa to set the volume to 10. At that point, as I rather painfully found out, you've got to shout a lot to get it to pick up your voice. Again, I was testing with Beta software, and maybe this is a feature that will improve over time.
In theory, you should also be able to use HDMI-ARC to control TV power with your voice, but I couldn't actually get that function working on a Sony TV. That may be due to smaller model differences, or even the slightly different Alexa feature set we get in Australia. There's no real support for channel or input switching on the Sonos Beam in any case (or at least not yet) via voice, but you may find your voice inputs limited to simple volume shifting, as I did.
The other limitation of Alexa is one that's essentially Amazon's fault rather than Sonos', and that's around workable music sources.
Alexa only fully "talks" to Amazon Music and Spotify, a very far cry from the wide variety of sources that the Sonos App can talk to. Alexa will play and pause tracks you queue up from other sources, but you can't search for them, or ask it to play using those services using your voice.
Sonos is promising big things for the Sonos Beam, with AirPlay 2 due in July, and Google Assistant set to appear at some point this year. Once it has got those two features on board, the Sonos Beam will become a lot more appealing, simply due to the larger flexibility in voice commands that will bring.