LOL at using Windows on a high DPI screen. Windows 8 improved a lot, but using any Desktop apps (Photoshop, IE, Chrome, etc.) is horrible, everything is super tiny. They haven't really given much though to scaling yet, even in Windows 10 scaling is still being figured out.
This is so patently false I'm not sure if you aren't just trolling. I use windows 8 on a 150 DPI screen (28" 4k) on my work desktop and a 220 DPI screen on my laptop (rMBP). Both have no problems, and most commercial apps already support it (chrome, IE no problem, I've heard phtoshop is ok as well).
The post you are responding to is a bit hyperbolic, but "HiDPI" scaling on Windows is still pretty hit or miss with lots of major apps. (Chrome isn't one of them, despite its mention in these posts -- since Chrome 37 it has done proper DPI scaling on Windows, and that release has been out for quite a while now).
Photoshop (since it was also mentioned) has very limited support for real scaling (beyond the OS's default of render as if on a low-dpi screen and then bitmap scale the UI up, which looks horrible, especially when combined with an app you are using to do precise bitmap editing) -- the only meaningful option it gives you is to scale everything in the UI up 200%, which is better than nothing (and what I have to do on my 3840x2160 Toshiba laptop to get a usable UI), but not a really flexible solution and even this is considered an "expirmental feature" in the very latest version.
Adobe Lightroom, on the other hand, has effortless scaling and just works great on screens at any DPI.
The point being there is plenty of support in the OS for apps that effectively scale, it is just that there are a lot of Win32 legacy apps out there which would require a near rewrite of the UI layer to scale well, it is by no means something the OS handles for you automatically (beyond the clumsy bitmap scaling default) if your code targets the older UI APIs, and there are (still) plenty of gotchas you do actually run into when running Windows apps on high DPI screens, though things are certainly improving in this regard.
My wife is into Photoshop (as a designer) and Illustrator, but uses them on Macs exclusively, so I can't judge there. It is crazy: Adobe got flack for not supporting macs well enough with GPU acceleration when macs were going out of style....and now, Macs are back with a vengeance and they are neglecting Windows instead :)
I have rMBP too and no I'm not trolling, you must not be using it at the full resolution. If you use Windows at the full resolution for the device, everything gets extremely small, so you have to increase the font/title bar size, even then you have to turn on zoom on IE and Chrome and the UI elements on all Desktop apps is incredibly tiny. Playing games is incredibly annoying because of how tiny everything is. Most Desktop apps do not support scaling in Windows the way one think it would. If you are fine with using one Metro app (or two with one pinned) at a time, then it's perfect.
Even in Windows 10, the new update has issues with scaling. It now caps out correctly (1920 x 1200), but it is blurry as hell.
