Well again I'm all about "that depends on the workload", and environment and so on. Personally I'm not sure I would use ZFS og BtrFS on a laptop or any other FS that goes to great lengths to preserve my data perfectly, simply because the laptop has so many other reliability issues that external backup is the only solution that is good enough. So rather than paying the price for reliability all the time. I would run "unsafe" + backup on my laptop and get the performance advantage. At work i'd much rather use ZFS on BL460c G7 blades with HDS USP-V or AMS2xxx storage backends. They are not really slow even though there are disks inside.