I've worked with several network device vendors in my 10+ years of being in the industry and my favorite continues to be Cisco IOS. Overall, Cisco IOS tends to be the most stable, the most intuitive, has the best TAC support, and has the best knowledge base articles and white papers.
For the longevity of a product and intuitive design. But it is a matter of opinion, and if you are more comfortable with Windows, then stay with Windows.
By this point, there are several "flavors" of the Cisco IOS such as XE, XR, and the standard Cisco IOS. While they are all fairly similar, there does exist syntax differences between them. It would be ideal if at some point in the future, Cisco is able to unify all of them into one standard operating system which would use the same syntax across all platforms.
While overall Cisco does a great job of QA'ing their IOS, no matter the release, there's always some minor bugs. I think it's important that Cisco continue to pour resources into their QA team to test their software.
While I'm very familiar with the graphical readouts of "show processes cpu history" I would love for Cisco to eventually find a more intuitive way to display this data. I can't begin to count how many times I've had to teach more entry level (and even mid level) engineers how this graph is interpreted.
I do wish that Cisco had something similar to Juniper's "commit check" or "commit confirmed". This helps validate the changes you're about to apply, and catch errors, so that you have a better idea of the impact of the change.
The data that Cisco IOS is able to provide is extremely relevant, it's fast, and it's intuitive. I also love that you're able to leverage things like macros or EEM scrips to run multiple commands at once. This is especially useful when you have more junior or entry level engineers in your environment and you want to provide them with a "shortcut" by having them type a single command to execute multiple commands.
We have found other Cisco software to be filled with added functionalities as compared to iOS. New NCS software has certain programmability features that are advantageous to legacy iOS software but are more complex to use for some users. Hence, we still have most areas of the network that functions using iOS software.
macOS just makes sense to me. Each OS has its pros and cons.. macOS works for me. It's well designed, intuitive, and efficient. But it's not cheap... well, macOS is basically free, but you need the hardware to run it, and the hardware isn't cheap. Pick the right tool for the job and for you. And even though macOS may not be thought of in an enterprise environment, it works remarkably well if configured properly. Tools like DEP and ABM from Apple enable device management and lock them to the company. Use an MDM like Jamf to push policies and packages. Jamf can also manage accounts and authentication. JumpCloud is another great product for account management. Although it might not be all included in the box, with the right knowledge, you can build a robust and versatile enterprise Mac infrastructure. You can even do zero-touch deployment in most cases with the correct setup. And Apple employs engineers to help you get it set up right.