I recently installed on my main Windows-PC computer a (rather old) LCD display from Hyundai: ImageQuest Q17. I wanted to improve significantly the correct color calibration. Fortunately, I could get a Pantone ColorVision SpyderPro for the weekend.
It was only a matter of minutes to setup the sensor and run the calibration process. Everything goes smoothly since it is a completely automated process (you only have to wait while test colors change on your screen until the correct calibration is reached).
The result is impressive. Before doing it, I knew that my colors were slightly off. After, the white and greys are so much better that it was immediately perceptible.
Great product that exists both for Apple and Windows.