I first tried Defraggler (the free version) years ago, and I have been trying its newer versions from time to time. One of the features it is lacking is the ability to defragment the hibernation file at boot time. It is not listed at http://www.piriform.com/docs/defraggler/technical-information/boot-time-defrag, and it is not defragmented, indeed.
Some other free defragmenters can do it, and this is one of the features that makes me choose that other software. I hope that Defraggler will get that feature some day.