That said, if you do feed it bass-heavy material, it can start to sound crunchy (read: distorted), especially if you crank the volume. To me it sounded best at midlevel volumes and like a lot of these smaller speakers, it performs best in the midrange, so it sounds better with acoustic material and lighter listening tracks. It's also makes a decent little speaker for movie watching on your notebook or tablet device.
The Micro has a built-in rechargeable battery (you charge with an included Micro-USB cable) that's gives you about 5 hours of listening time. That's not great, but it's not bad either, and par for the course for these smaller speakers.
I've reviewed a handful of this tiny wireless speakers and while I can't say the JBL Micro Wireless is a steal at $59 list, it's pretty fairly priced. You can step up to slightly more expensive Bluetooth speakers such as the Logitech UE Mobile Boombox, the AT&T Loudspeak'r, or even Logitech's older Mini Boombox, and get slightly better sound. iHome, Panasonic (SC-MC07) and others also make small Bluetooth speakers and plenty of ball-shaped wireless speakers are available. But I liked the Micro's hockey-puck form factor -- it rests nicely on a desk or can be propped up vertically (or hung somewhere). It also slips easily into a bag (or a jacket pocket) without taking up much room. And the integrated line input cable is an added bonus (there's also a second line-in port if you opt to use an optional extended cable).
In all, the JBL Micro Wireless is a well designed tiny portable speaker that's reasonably priced ($40-50 would be better, of course). While it doesn't deliver great sound, it plays louder and sounds better than its size would indicate, and should make for a good traveling companion for those who want to augment the sound of their laptop, tablet, or smartphone speakers. Recommended.