I'm in the same situation, using Arch for almost everything but needing Windows around for work (and being able to run a few games that won't on Linux or via Wine is nice, but with Wine 3 supporting DX10/11, I'd probably ditch Windows entirely again if not for work). With 1709, it's gotten to being at least a bit of a fair fight.
* The privacy issues remain a major factor for me.
* Windows just works 99% of the time, but if something does go off the rails, I know I'm in for a bad day. Linux just works 98% of the time, but it gives me the freedom and documentation to fix whatever it can throw at me. When fixed, it also tends to stay fixed a lot better than Windows.
* 1709's update throttling is a massive improvement over 1703 and earlier, but Windows is still a whole lot less respectful of bandwidth (and other resources) than Linux. I've only got either a 1.5 Mbit or 4 Mbit downlink, and trying to get Windows and gaming to coexist on that is still a pain sometimes. On the other side of that coin, the Windows desktop has noticably (10-15 millis? 144 Hz, so it isn't going to be a frame delay) lower latency than X11 + libinput + Nvidia proprietary (non-libinput seems better and AMDGPU seems better), and doesn't have to deal with pulseaudio.
* As a concise bullet point in case you don't care to read the rant below, Windows' UI feels really slow and awkward compared to an environment properly customized to fit your workflow, and Linux allows that customization far more easily than Windows. Windows' UI also just fumbles critical things unreasonably often; recently when trying to fix something trivial on a friend's system, I actually had to go find the old-school control panel's executable *using a file manager* because it had inexplicably disappeared from every other method to access it, including searches. In Windows' favor, Gnome 3 makes dwm/explorer look like some kind of divine inspiration in comparison, and Gnome 3 is likely as not what you'll get if throwing darts at a board to pick a Linux distro.
* <rant> I don't understand how people navigate Windows' UI in a timely manner. Let's say I want to open some program; this should be a solved problem. In Linux, I've configured that menu key nobody ever uses to open a terminal, so it's menu key -> type first few chars of program name -> tab complete -> enter. With virtual desktop abuse, the extra terminals left hanging around are no problem, and winkey+[number] to go straight to a desktop makes virtual desktop abuse easy. In Windows, the equivalent launch sequence is winkey -> type first few chars of program name -> wait for search to figure out what programs or other things might match -> select the right one -> press enter. The waiting takes as long as the entire launch sequence on Linux even on a fast machine, typing the whole program name doesn't solve anything because the search is janky, failing to wait sometimes opens Edge+Bing searching for whatever it is you typed instead of doing anything locally, and winkey+R isn't a good enough substitute because it just doesn't know what all the things I might want to run are. So the pseudo-CLI way is a bust, what about pinning things to the taskbar? If it still worked like it did in XP that'd be fine, but now running programs take the same space as quick-launch items, and launching multiple instances takes two clicks with precise aiming between them on top of the initial wait thrown in there because I don't really want a taskbar taking up my screen space all the time. Desktop icons? To access them without minimizing windows requires more virtual desktop abuse, virtual desktops aren't nearly as nice on Windows as Openbox, and the process (including mouse aiming) still takes longer than what I do on Linux. This is a fairly trivial example that doesn't waste that much time, but Windows is packed full of these little annoyances - on average, interactions with Windows probably take me at least 50% more time than it would to do the same thing in Linux. </rant>