I have to support multiple OS, so I did insider preview on one of my extra machines. I've upgraded a couple of other machines (Win 7 and 8.1) to see how the process went. For personal use, it's just fine. I haven't run into a lot of the problems that some users have reported. The support was there for most of the programs I use regularly, including a lot of open source programs. My biggest complaint was that I had to disable drive encryption in order to upgrade, and then my preferred encryption program doesn't work on 10 yet. No big deal...I can use something else for the time being, but still irritating.
If you dual boot on a single drive, it's not so bad, but if you have each OS installed on a separate drive, it won't work at this time. Again, no big deal for me, but a friend of mine spent days working on that until finally giving up and rolling back to 8.1.
For business use, I would not switch without a lot of testing. I'm planning to set up another machine on my work network and see how it goes. But in truth, I'll probably wait another 6 months at least before I start upgrading business machines.