It depends on how long you intend to cellar them.
Bottled wines age faster, however, bulk storage especially if you are wanting a heavier oaked wine, gives it time to settle into itself a bit more, smoothes it out in my opinion. I don't bother too much with bulk storing whites unless I have run out of bottles.. ( happens frequently)
I know there are long chemical chain reasons for bulk storing.. but I'm not much of a scientist.. one of the others will have to jump in and explain the science behind it for you.
Allie