IMac :: Built In Speakers Or Stand Alone - Better One?

Which speakers are better, the ones that come built-in on the '09 24" iMac or Logitech X230? I'm not sure what the iMac's speaker stats are, but here are the stats for x230's:

# Total RMS power: 32 W RMS
Satellites: 12 W RMS (6 W x 2)
Subwoofer: 20 W RMS
# Total peak power: 64 W
# Frequency response: 40Hz - 20kHz
# Drivers:
Satellites: (2) 2" drivers per satellite
Subwoofer: 5.25" ported driver
# Speaker dimensions (H x W x D, cm):
Satellites: 20.3 X 6.4 X 7.6
Subwoofer: 22.9 x 15.2 x23.5
# Signal-to-noise ratio: >96dB

Reason I ask is that I have the x230's and they're considered as cheap speakers, so I don't know if I should use them with the iMac or not. The one advantage I see them having over the iMac's is that they have a 20w subwoofer, but I don't know if the satellites are better or not.