Windows 10 is good, sure, but don't be in such a rush to upgrade that you get suckered in by this (fairly obvious) email scam.
As spotted by Cisco, some scammers are taking advantage of the reservation system for Windows 10 to send out malware-ridden emails, posing as Microsoft. The email pretends to contain the installer package for Windows 10, while really carrying a nasty piece of ransomware called CTB-Locker, which will encrypt your files and hold you over a virtual barrel for payment.
The email goes to a few lengths to appear legitimate — a spoofed email address, so it looks like it comes from [email protected], and disclaimer/antivirus messages that give the impression of authenticity.
But all the hallmarks of an email scam are still there: missing characters, eigth-grader writing style, and, of course, the fact that Windows 10 is installed on your desktop, not through an email attachment.