What are the best desktop environments for people migrating from Windows to Linux?

Cinnamon is still not ready for prime time. It tends to be buggy and unstable. For a stable conventional desktop, I recommend Xfce or MATE instead.

MATE is my second choice after Xfce. It is a stable conventional desktop. Owing to its intuitive design, it is easy to configure and use.

Runs good

KDE is bloated, buggy, and unstable. It can also be confusing for new users. Linux Mint will be dropping KDE from its lineup and keeping Cinnamon, MATE, and Xfce. The only reason I would recommend KDE is if you have a multiple monitor setup and want to use the center or right-hand monitor as your primary sc...

"Raw" Xfce can be ugly, but the Linux Mint implementation is beautiful and functional. I have been using it productively for years after using both Windows and Mac OS.

Elementary OS has a consistent visual language, and a growing set of third party apps that were designed specifically for elementary. It runs great, even on older hardware.

I always go back to Xfce. Ease of customisation and how lightweight it is results in something I like the look of without it drain a lot of resources.

No problem for my mom, neither any client I ever migrated (with a lot o fear from their part before using for the first time), the first impression is always: WOW! So fast!...

A great choice for people switching over. I knew of Ubuntu when I transitioned, but I wanted to keep most of my games and programs. This is a good bet on compatibility, when in the transition.

Beautiful, fast and stable. :)