I'm still using old Ontrack SystemSuite 4...with JetDefrag.
I like it because it defrags the files into "clusters". All the .dll's and such kept together,
frequently modified, rarely modified, etc. are kept seperate.
It will also defrag the registry, and your boot sector.
I don't know why but I never got O&O defrag to work correctly with scheduling. It would just run once at scheduled time, despite choosing to defragment every day at given time. Diskeeper works fine in all ways, so that's what I have kept using.