The X1 has a better signal to noise ratio, as well as higher peak handling.
Both are rated 20-20000Hz, which, considering the size of the woofers in particular, I would take with a grain of salt.
Or a barrel load of salt even
You're more likely to actually get about 35-18000Hz out of that system. If you're going to be using it mainly for MP3s, then it doesn't matter anyway
Regardless, the X1 is better .. on paper at least
EDIT: I concur with TVman on the Logitech speakers. As it happens, I have that set.