Without a doubt, the Bang & Olufsen Beosound Level is the prettiest and best-sounding wireless streaming speaker I've encountered that operates on both AC and battery power. It holds true to the aesthetic spirit that's long driven this legendary Danish electronics brand, ever striving for a magical fusion of design and technology. But be forewarned, buying into this functional work of art isn't for the financially faint of heart: A single Beosound Level costs either $1,499 or $1,799, depending on which model you choose. You might need to rationalize this luxury indulgence as a long-term investment; like the pitch proffered for a Rolex timekeeper, or an exotic Euro sports car. And like those rare goods, the Beosound Level has a sensitive nature that in some ways demands a bit of coddling (more on that in a bit). At the heart of this device (and a few of B&O's other Wi-Fi-enabled speakers) is a new, modular circuit core called Mozart, which the manufacturer says can be swapped out for another if the onboard upgradability ever reaches its limit.