I wouldn't bother if you're just a typical home user which many people here are. However, there are some nice benefits that @itimpi has mentioned. Bit rot detection is nice but a rare occurrence and hard drives are designed to catch this so is it worth it just for that? Maybe. ZFS also has snapshot but would you use that? No. The one thing that I like is that ZFS supports inline compression such that when you save a file it's compressed and then saved to the disk in the compressed state. This can save some space for you. However, you need to keep in mind that reading and writing files requires the extra step of compressing and decompressing it. Will unRAID support that feature? I'm not sure. Another cool thing is deduplication but this requires massive amounts of memory and some planning of file block sizes since the file block determines how much memory is used to keep track of all the blocks. There are also ways to improve performance like ARC/L2ARC and SLOG/ZIL. Are you confused yet? Join the club. It's not an easy file system to just plug in and use. So when you take all these "configurable" parts away you're left with "just another file system".
So for now I don't see a benefit but as people use the file system and other smart people make it easier to use and/or set up then it will become "the next best thing".
This is what I'm hoping for. I see the array or caches as being synonymous with a ZFS vdev. The drawback is that you need to think about your setup before you build your server whereas right now it's all pretty simple with unRAID which is what I love about unRAID.
Forgive me but I think the following is a great explanation of ZFS. The link is to TrueNAS. Someone here needs to write up something similar but with reference to unRAID once ZFS officially shows up for unRAID.
TimTheSettler's post in Why use ZFS and can you convert existing array from XFS? was marked as the answer