>Can any body explain me a negative side? Whilst 100% is nice to have - it costs money. Historically lots of pro grade Nikon's like the F100 had 96%. In days not so long ago you had to get F5, 6 etc at F5 and F6 prices to get 100%. And so it is with digital D300/3 for 100% and D700 for 95%.
Photography is a bit like archery. A technically better camera, lens or arrow may not hit the target as often as it could if the photographer or archer does not practice enough.