If you want to use your computer for dual monitors, I would not suggest buying the NUC7 based on my experience. Trying to get them to work properly (and consistently) has been a major thorn in my side. In fact, I'm actually thinking of switching to an ITX build with the NZXT H1 case that just came out so that I can use a real GPU for that very reason. Maybe it's just me, but for the life of me, I can't get them working without major hassle (plugging and unplugging, power cycling, rebooting the machine, etc etc).
Handoff, AirDrop and Continuity all work fine with a supported replacement Broadcom wifi card. I haven't tried Sidecar since my iPad is too old / unsupported so idk about that. I bought my NUC7 before we had come to the conclusion that we could use adapter cards in the NUC8 in order to get fully working handoff and AirDrop so the NUC8 could also be an option if you really want Handoff and Continuity. But if you were to do that, you'd be sacrificing a faster port to run your wifi card then running your system disk (afaik) at a slower speed. To be fair that was the gist of what I read, and I'm by no means the expert on the NUC8.
The only other gripe that I have is that the fan is significantly louder than the Haswell NUC that it replaced. I have tweaked the NUC7 fan profile in the BIOS with settings found in this thread so it's a little better than Intel's native settings, but even after tweaking, when the fan ramps up it gets louder than I'd like. The big draw for me to the NUC line has been a powerful machine in a tiny case that is pretty quiet. I would not call the NUC7 a quiet machine, at least not the i7 variant that I have. If you have any other questions, I'll be happy to answer them for you.