I switched away from ZFS on root after using it for about a year. There were no actual problems, but I could never get over the fact that it's so complicated underneath I have to relearn everything every time I do any sort of advanced maintenance.

For example, I had to move between SSDs which is an absolutely trivial operation with any other filesystem if you know your Linux well. It took me maybe three hours of work on ZFS because it brings its own environment and does everything its own way, so I had to remember and re-discover a lot of stuff. The system booted on maybe 15th try.

If you are fine with this, or you're not going to use it on root, or you are a FreeBSD user, it's an excellent choice for pretty much any task.