I've added "other" to the poll because even if the question is "Which of these do you prefer", "other" or "neither" ate valid options. The question is very much like asking someone if they would prefer to be Christian or Muslim. Firstly it eliminates many valid (and indeed, major) options, and secondly it oversimplifies the issue that each major option has many variants.
Personally, I've used many operating systems. A few of them are: TOPS-10, RSTS, MVS, MPE, HP-UX, CPM, MPM, CPM-86, MS-DOS (from 1.x up to 6.x, and higher if you include embedded windows versions), Windows (from 2.x up), Linux (4 major distros plus others). And whilst I don't list them, I've been exposed to a stack of others including MAC-OS (both pre and post BSD).
As a developer, user, and supporter of users of application software, the OS is important to me, but I've used enough to be able to say that most "ease of use" arguments boil down to familiarity. The big deal for developers is number of users (sometimes), the API, the development environment, the availability of documentation/examples, and frequently what you have on hand at the time.
The more operating systems you're exposed to the more you learn that every one has annoying shortcomings that make you wish you were using something else. It's not that the grass is greener on the other side, it's frankly pretty patchy. Every time you're in one of those dry, dead patches, you gaze over and see the verdent green somewhere else (and maybe forget for a moment that they hide their own dead dry patches).