That thinks Chasseur d'Images:

Monkey or spyder?

Why do you need to calibrate your graphic chain? If the aim is to improve results without too much hassle, then the Munki is an excellent solution: simple and quick, with no restricitve manipulations. Users with greater ambitions, who seek a start-off tool that can be developed tp deal with complex demands, will prefer the Spyder... although this requires a little patience when measuring the color patches. Photo clubs seeking a collective solution will have to opt for the Datacolor, because the Color-Munki only permits three installations and cannot therefore calibrate as many computers as the Spyder3 Studio. The two solutions are pretty much the same price. Personally, I would go for the version whose more advanced options look further to the futur, i.e. Datacolor's Spyder3 Studio. But less confident users will prefer the Munki for its user-friendliness.