There is no such thing as a perfect OS.

When people ask me why I prefer Android and Linux Mint, the answer is because they just work for me.

Would I recommend them to others? Well, that depends on their needs. Not everyone's use case fits either OS. While Android fit a wider set of users, Linux Mint doesn't. That's why I ask what do they need, even expect, to use their smartphone or computer for, since the answer depends on their user case.

The OS that better fits your needs, is dependent on things like what you are going to use your computer for, what software you need to use, among other things. Trying to say that any OS is the best, is depends on what the end user needs and not on the OS itself.

There is no OS that fits all user cases, so the best OS for a given user case depends on the details of each user case. Besides, there is no such thing as a perfect OS, since each OS is made to fit a certain set of needs.