The SoundTouch 20 has a sharp look and solid sound that could have made it an ideal WiFi music solution -- if it had more features to justify the price.
The SoundTouch 20 is neither flashy or flamboyant, and PC Mag calls it "elegant," while CNET notes that its footprint is "relatively compact." With the Bose name attached you should expect a lot audio-wise, and What Hi-Fi calls the performance "good, but not amazing" with the sound being "clear" and the volume "never an issue."
Like Sonos, SoundTouch supports Pandora and playback from your personal music collection, allowing you control via your Android or iOS device. However, the list of supported services is still pretty small, and there aren't any heavy hitters in their arsenal aside from Pandora. iOS users can get around the lack of services via the SoundTouch 20's AirPlay capabilities; Android users are just stuck. Bose promises more on the horizon, but you could pick up a Sonos instead and get more services for the same amount of money.
For $399 you shouldn't have to wait for a firmware update to start really using your product. If you're a Bose fan who doesn't mind the current limitations, you might enjoy the SoundTouch 20. Or, for the same price, you can pick up a Play: 5 and get all your favorite services right now.