I have tried two different Spyder calibration tools in the past (I got a "better" one after having issues with my first one... but only with the same results). I had no end of problems. The two main ones were that I would run a calibration and the whole screen would go the wrong color (like a red tint or one time a green tint). I would have to calibrate repeatedly at times with all the curtains closed and all the lights set on dim, just to get a normal looking screen. The second main issue (that I assume came from calibration) is that it seemed to do something to my computer itself.... when I would view things on the monitor it would suddenly "jump brighter" I would than be working with it and things seemed normal (but perhaps slowly going dimmer again?) and than jump brighter again. When I got my new computer I kept my monitor and have not used a calibrator system since. However I am moving from offering digital and into offering prints and my prints are coming back abit off with vibrancy and exposure, so I will need to calibrate. I am looking at the Color Munki Display since WHCC recommends it. I guess I just don't understand... if I calibrate how does WHCC have the exact same color profile? And how do I avoid the issues I had last time? I feel very leery to try this on my new computer after last time.