Put most simply:
1. All screen readers currently available and supported, and by that I mean JAWS, NVDA, Narrator and VoiceOver (on the Apple Platforms) handle most of the functions used by most users, across settings, be they at home or in the workplace, very, very well.
2. Each has specific things it may do much better or much worse than one or more of the others.
3. It is often not the screen reader that is a problem so much as what it is working over top of.
4. Any screen reader user should, ideally, expect that there will be the occasional situations where "my favorite" is not the best for doing a given task with a given program. Given that JAWS is the only one in the list above that requires licensing (and use in 40-minute mode is allowed even if you don't have one) and NVDA allows the creation of a portable version on USB media, a wise user will know enough about using the core functions they usually need in two or more.
5. Narrator is going to become a major force on Windows much like VoiceOver has been on the Apple platforms for years. Microsoft has clearly made a huge commitment to accessibility unlike anything they ever had done in the past. This being the case, one would be wise to learn the functions of Narrator one commonly uses with either JAWS or NVDA as one's primary because it will be available, without cost or installation, under Windows 10.
There is no best screen reader sans the specific usage contexts in which it will run. I've seen that from every angle so many times I don't care to count. Asking about what's best or asserting what's best sans very clear defining parameters regarding usage is a fool's errand.
A screen reader is no different than other tools, including physical ones. What's best is directly defined by what one needs to do with it and how good said tool is at doing it.
Brian - Windows 10 Pro, 64-Bit, Version 1903, Build 18362
The color of truth is grey.
~ André Gide