Within 5 miles of our farm there were 3 White planters that went to another color just this past year. One went Case the other two Kinze. Two years ago two others switched one went Kinze the other Deere. Now I will say the White meter is very bulletproof. It can be a little aggravating changing seed discs or air pressure in corn, but over the long term they won't cost much to operate. The downfall to me is the weight and this never ending circus of toolbar and tire designs. The row units are still too close together and while the new toolbars are better than the 8100's(splitters) these screwy tire combos are a joke.
I had a real hard time going back to the finger PU on the Kinze, but I must say for less money I think I have the better planter for my farm. Here in Southern IL resale has started to suffer on the Whites as well. The bottom line is the White is a good planter and probably plants as accurate as anything out there. If I were going with a straight 30" row planter w/o fert I would probably go White. But for 15" rows and/or with fert my personal preference would be green or blue(now red ones around here to speak of so I know nothing about them). In the end a big part of your decision will come down to how good your local dealer supports those products.
Like I said, hard one to discuss. We used to see some Kinzes a number of years ago, now they're nearly non-existent for a ways around here. Local Case/Agco dealer salesman a few years back said he had White planters outselling Case 9 to 1. That coming from the salesman himself and he has no reason to be biased toward either brand.