I've used DK since version 6.0 (using v8 now) and have never had any problems out of it, to be honest. PD might be a great program, but I've had really good luck with DK, so I've seen no reason to switch to anything else. I just setup my partitions to be defragged using "smart schedule" and it does its thing without me having to worry. On occasion, I'll go in and analyze the drives to make sure they're in good shape and for the most part it keeps my partitions in tip-top shape. I've noticed one thing for sure, though... I've installed it on friends' computers that are running FAT32 and it takes about 3x as long to defrag as it does an NTFS partition.