One distinct advantage of JKDefrag would be the optimization routines.
Where to put the defragged files - beginning of disk, etc. which has a lot to do with performance of your disk.
I run my optimizations by scheduled tasks at night, so I don't care how long they take.
What I care about is that they make my machine run at the fastest possible speed ("optimized")
It seems odd to me that you would ever run defrag tools manually and sit there watching what it does for an hour ??
Batch mode / commandline / scheduled tasks is key for me in this regard.
There is no doubt defraggler is darned fast though, so I use both. Defraggler is used more topically for a quick run.
