I contract from time to time, I'm very familiar with Windows 7, used it heavily alongside Ubuntu on a variety of hardware. I find various sleep, suspend and hibernation issues on all versions of Windows from 7 back. Apparently I'm not alone, Google this phrase: "windows sleep problem".
The sleep/hibernate and wifi issues never stopped, and I gave up and bought a MacBook.
I might go back for another whirl with an X1 Carbon soon, though. But honestly, I'll probably run Windows as the primary OS and just have Linux VMs.