Thinking of Switching from zipabox: anyway to use wired sensors with a smartthings system?

This might help:

How to Get Started Creating Complex Rules in SmartThings (2017) (SmartThings Classic)

As far as specifically your question about sunset/sunrise, yes, that’s part of the official features.

Rules are called “ automations“ in the official features. One of the popular unofficial communitybuilt rules engines, webcore, calls rules “pistons.“