i've had a Tivoli PAL for awhile now, and really enjoy the sound that comes out of it. i would describe it as warm and rich, with a mid-bass hump, and rolled off at the very top and bottom. very nice, full mids.
it works especially well in quiet environments, and can surprisingly fill a small room. outside, it won't overpower the din of a crowd, but i can't think of a better option for a patio or beach in such a small package. it won't fare well in windy settings, though.
battery life is good. i get around 8 hours on a charge, and replacement battery packs can be purchased, and easily installed.
as a radio, the tuner is one of its major strengths. it really locks onto signals, and allows for ultra-fine tuning. if you're going to use an ipod, i strongly suggest running a cable from the line-out rather than the headphone jack, as it sounds better and more effortless to my ears.
the designer, Henry Kloss, knew what he was doing. one high quality driver will always sound better than two crappy ones.