As far as the its audio quality goes, as you might expect from a speaker this slim, it's not exactly rich in the bass department; even if the box it comes in says it is. However, that doesn't mean it's totally lacking bass, but we found the speaker's overall sound to be underwhelming with music and preferred using the speaker for augmenting the soundtracks when watching videos.
The key thing, of course, is that the speaker plays louder than your typical internal laptop speakers do--and it sounds better, too. So while it's not going to blow anybody away with its audio quality, it's certainly good for making a business presentation to a small group and watching a movie in your hotel room later. With a cost of about $35 online, it's a decent value.
If you're comparing similar products, the Philips isn't the only option. Logitech makes the Z205 laptop speaker, which costs about the same price. It, too, is USB-powered, and you can clip it on to the top of a Notebook or place it on a table.
The Philips and the Logitech speakers sound very similar, but the Logitech is slightly more compact--it's not as wide--and has an aux input for other audio devices, though you still have to have the unit connected via USB to power it. We'd probably give the Z205 the edge by a hair, but it's worth noting it doesn't include a carrying pouch as the Philips does.