While the Echo stands out for its assistant abilities, it's still basically a speaker and in that aspect it mostly succeeds. From a visual standpoint it's rather unassuming, but GigaOm still calls it "elegant." And, with a circumference just over three inches, it won't take up a ton of space on your desk or sideboard. But don't think you can take this to all your parties and picnics -- Echo has no batteries, meaning it needs to be plugged in. Aside from that minor issue, the size and shape don't impact its overall sound at all. Business Insider says it sounds "pretty good" and CNET likes how it "projects so-called 360-degree sound" though they were disappointed to find that at higher volumes it distorts, sometimes "badly."
However, the big draw of Echo is how it can serve as a personal assistant, letting you tap into news, weather, information, music, alarms and other services. CNET says it's actually "one of the better voice-controlled devices" when it comes to understanding the commands you bark at it. Sadly, its limited scope in what services it works with is Echo's major drawback. Gizmodo says it "falls short" due to its limited range of integration, and GigaOm calls it "Echo's Amazon-centric view."
An Amazon-centric view should be expected given that this is an Amazon product, but it also means it might not fit into your particular lifestyle. Echo is not a bad device; it's just one best suited for people already heavily invested in Amazon's ecosystem, making it ill-suited for anyone just looking for a speaker. But, if you're the kind of person who likes to try out new things and explore the world of connected services, it's certainly worth a look -- just make sure you've already signed up for a few Amazon services first.