Bought it yesterday, and I've played maybe a couple of hours. I rate it an excellent port so far. It appears to be the full game, feature for feature identical to the PC version. No corners cut that I've seen.
It controls very well with the JoyCons, too. Navigating menus isn't quite as fluid as it is on PC, but I can't imagine how it could have been done better. Plus it can be controlled entirely with the touchscreen, which I think is a first for the Switch since most developers seem to forget it even has one. The UI is generally large enough to be easily readable in handheld mode, though I wish it were a little more consistent because some text can be quite small.
I'm still in the early game and haven't uncovered a lot of the map, but oerformance so far is very good, and it looks gorgeous. AI turns take longer than they do on PC, but this is because of the Switch's weaker CPU compared to the PC.
I hope this sells well enough for them to release expansions in the future.