What lens, how big is the sensor, what technology behind the sensor?
See with MP alone as factor you get nowhere. A camera is allot more then an amount of pixels. It has light meters, glass parts, moving parts to focus and zoom, chips with programs to change the signal data of the sensor into a digital file and write it away and so on....
Not to mention usually more megapixels if the rest says equal means worse quality.
For instance DSLR's have a much bigger sensor then compact cameras and yes even superzooms. This means that on those sensors the pixels, the light recieving sensors, are nice and big.
On a smaller sensor with an equal amount of pixels the pixels have to be smaller. Smaller pixels have a harder time capturing all the photons and are earlier "full" aka a harsh white value. Also with so much packed on such a small area the electronic influence over each other gets worse, noise happens.. and image quality gets worse.
So when you have a 12Mpixels DSLR and next to it a 12Mpixel superzoom they might look the same, but the DSLR makes better quality images, well looks wise. The colors remain better, the dynamics between shadow and light are better. The true quality of the picture is what the photographer has to make from it, only he or she decides when the picture and how the picture is taken after all ;)