This is the third ultra-portable mini speaker/system I've bought to use with my many mp3 players, phones, etc, and it's the one I use all the time (the others being Creative and X-mini). Despite lacking stereo, it gives a great, clear sound and makes listening to speech an absolute pleasure. While I prefer to fire up a larger sound system for listening to music at home, this Mighty Little Speaker has become invaluable for audiobooks and podcasts. I keep these on my Nokia phone and plug it into the speaker - the whole arrangement can then easily be carried around the house, left on the counter in the kitchen, hung on a hook in the bathroom, you name it. The sound is rich and clear - quite amazing for the size and price. I'd very happily use it for all sorts of listening while travelling.
Incredible battery life, well over the advertised 24 hours - I've had the speaker over a month and used it heavily while recovering from an injury... and the first set of batteries hasn't yet run out.
Ultra portable - the lanyard, case and carabinier clip are really nice touches.
Very sturdy - I haven't travelled with this yet but would fling it in a backpack without a second thought.
Takes regular batteries - no charger to worry about when travelling!
Nifty design - it's not beautiful, but the case, the neat cable store and the chunky battery compartment access are satisfying.
Cable is a little short - but at least it doesn't get in the way
No volume control on the speaker itself.
Overall, I recommend this unreservedly, particularly for listening to speech, or for travelling. I bought a second one as a gift for an audiophile friend and was worried that he might sneer at its lack of stereo - but he loves the speaker and uses it daily to listen to the news from his netbook.