You see, one of the great pleasures of using an iPod touch or iPhone is the ability to twist it from portrait into landscape mode. The accelerometers in the device spot you've done it, and instantly (well, most of the time) rotate the screen to match, giving you video playback in the correct 16:9 ratio or allowing you to flick through your music collection in Cover Flow mode.
The i-Station 25 lets you do this while your touch or iPhone is in the dock, it's own accelerometers recognising the change in orientation, and switching the signals going to speakers so that the top two speakers now deliver the right-hand part of the stereo signal, while the bottom two deliver the left-hand portion.
Flip the i-Station back to portrait mode, and it (and hopefully your iPod) switch straight back. A blue LED-lit indicator above (or to the right of) the iPod confirms which mode the dock is currently working in. The trick also works with a 4th gen iPod nano, but without the clips holding it in place you're putting a lot of strain on the connector.
The i-Station 25's other selling point is that it doubles as a portable system. You can happily plug in the standard-issue wall-wart power supply and charge your iPhone or iPod, but the speakers will also run from four AA batteries if you feel the need to take your music outside.
Now for the bad news. In its portrait orientation, the i-Station 25 is not a great sounding speaker dock. The sound is thin, boxy and muffled, with little sense of stereo separation, and it's hard to find anything that really sounds great on it. It fumbles the funky drums and syncopated guitars of Maroon 5's Make me Wonder, giving the sort of sonic performance we used to expect from budget brand micro stereo systems. The driving beat of Ladyhawke's Dusk 'til Dawn is rendered impotent, with the big beats made to sound dull and woolly.