Right now, macOS. Switched to it when I started uni and I'm never going back to Windows. The main reasons are:
- unix based
- generally easier to manage software
- the OS itself has most of the basic utilities already packed in and most of them with the right features. I rarely felt the need to install new software to cover lacking parts.
Also, generally stuff is packed fairly well, with care for user experience.
I will say, I'm dipping my feets in linux as well, and it looks like a lot of distro now are mature and accessible. If I ever were to buy a second pc I would seriously consider the penguin.