Over the years iOS updates have been hit or miss for me, performance-wise. I'm concerned about it becoming sluggish, so I'm hoping I can hear from some of you early adopters with the same model.
I've held off on upgrading as well on my iPad Mini 2 (or Retina as I know it). But the new OS is so nice I'm sure I will do the upgrade soon enough.
Now is the best while they are still signing 9.3.5. Once they stop signing there's no way to test iOS 10 and go back if you are unhappy.