Measuring Paper white feature with Color Navigator pro any good?

[jyannakas]

I' m using an Eizo CG243W with the Eizo easy pix bundled Spyder 3 colorimeter.

Has anyone got decent results from the "measure white" feature of Color Navigator?

Is it reliable or should I go straight for i1 Pro spectrophotometer?

I 'm asking because when i use it even a few cm movement would result in great differences
for the chromaticity coordinates.

Bear in mind that I don't won't to spend 1500 euros for the i1 Pro spectrophotometer unless it's really necessary.