I've just bought the X-240 speakers and the design is excellent. I love the cute little satellites, they're well angled to point directly to you.
If you like your music SERIOUSLY bass heavy, then these are a good buy. I have the sub set to about 25% and in loud paced music it's still too "thud" rather than "music". Basically, it's a GREAT kick-drum, but bass guitar is poor.
I've just had to replace my Harman Kardon Soundsticks (and coz I'm feeling poor, I didn't want to replace the £129 speakers at the same price). I saw a good few reviews for the X-240 and I guess for the money, they're a good deal. Anyone who tries to persuade you these are "HiFi" needs to be led into the street and put out of your and everyone else's misery. The sound is cloudy at best - there is very little clarity. It's kinda like over-hearing someone else's headphones.
The Logitech site claims frequency response of 40Hz-20kHz. The Sub feels like it's going lower than that, and although I can't prove, I doubt the speakers have any tonal power at 20kHz. They might be able to get there, but they're soooo quiet you'd never hear it over the midrange.
Gaming improves a bit because most of the noise is mid-low range. I am currently trying to figure out the wiring loom from my old SoundSticks as only the bass died and if I can get my old satellites working with my new Logitech Sub, then I reckon I could be on to a winner.
Overall - they're good for the money, but if you actually LISTEN to your music then spend an extra £20-30 and get something that much better.
Ooh, and to further everyone else's sentiment - the MP3 holder is rubbish. I'd rather blu-tack my iPod to my desk than use that cradle. You will have to provide the USB interface and dock cable to get this to work. The volume controller will allow you to play your MP3 player through the speakers but will not charge it. You will need to connect the Sync cable for this.