See: http://www.dxomark.com/index.php/Cameras/Camera-Sensor-Database/Pentax/Q
And for all the detailed measurements and results:-
http://www.dxomark.com/index.php/Cameras/Camera-Sensor-Database/Pentax/Q#tabs-2
A quick comparison to the Nikon J1 (with a 1" sensor) and the Olympus XZ-1 (with a 1/1.7" sensor) reveals that the Q is rated in between. Still, don't hope for higher ISO performance for lower noise, as the standardised threshold limit for "tolerable" noise level is at ISO 189 only, i.e., less than ISO 200.
So, how about the differences when the Q is compared to micro-4/3 or even APS-C entry mirrorless cameras of the latest. See this comparison against the Oly E-PL3 and the Sony NEX-C3.
Of course, you can continue to change to any other DxO tested cameras and compare endlessly till the end of the day! I would better stop here now~ ;-D