Well, I was dealing with Microsoft back in the early 80's.... professionally due to the nature of my work and that went on for many years, so I'll keep the dirt under the carpet! Needless to say, MS has a poor history of writing OSes... and I have a licensed copy of every one ever released. Several are completely useless, like Win98 and WinXP 64-bit, and others too (Win 8 anyone?). Win 7 Pro 64-bit is decent... but I only run it as a VM under Fusion (VMware on OSX) and only for a handful of applications that I use for 8-bit hobby stuff. WDC Tools, Dataman programmer, Atmel programmer, Quartus and it's programmer, ExpressPCB and maybe one or two other bits.
Microchip inherited WinCUPL, as did Atmel, IIRC. It's not on life support... it's just ancient code that hasn't died on it's own. My son also does a lot of software development for simulations, modeling, rendering, etc., he's not a big fan of MS OSes either, and prefers OSX (as do I). Still, I have an old retired colleague that is using Windows for 3D design and driving his CNC Router table and having very good success with it... so we can each have our own views... and mine go way back based on first hand experience with them.
These days, I use OSX as a main workstation with Fusion to run other OSes as needed (Windows, Linux, FreeBSD). I use FreeBSD for my router/firewall and my Plex media servers (on dedicated hardware). Linux is good for appliance stuff as well, but I don't like it as a workstation. It's been unreliable as a desktop and for virtual machines as well. It does work well as a 3D print server however... which is nice.
Come to think of it... I still have code kicking around for Xenix, BeOS, OS/2, QNX, Solaris and probably AIX as well.... but I digress....