Linux Mint is similar to Windows so you would pick it up faster,
The ++ Behind Linux are really that flash/java/firefox/ Office Apps / already installed so you can use it right out of the box.
Now "Lack of Viruses" is a partial myth. Linux doens't have the virus problem that Windows has for 3 reasons..
a. Linux is harder to code to make viruses for
b. Linux users tend to be more "tech" Savvy and don't click malicious looking links or download corrupted porn like the avgerage windows user who click every email they get and sends Jobba the Egyption prince money in good faith
c. Linux is about 5% of all OS's and so were a much smaller Target for viruses. Windows being the biggest has the largest amount
Linux Mint has many shot commands all available in the documentation. Alt F4 still works in Linux to close windows and with Linux you can make your own short commands as well.
Linux does excellent across most platforms when it comes to 64bit performance, but keep in mind there just isn't many 64bit applicatinos out there and a 64bit OS powering a 32bit application will run it no faster hten a 32bit OS.
The big + is all the open source software you could ever want at your finger tips and that list is growing Rapidly!
http://www.amazon.com/books/dp/0672336243 Covers the Latest version 12.10 & 13.04 of Ubuntu and it's only $18 on Amazon. Becareful you don't buy a book that covers a old copy of Ubuntu as it's changed quite a bit of the years.
Keep in mind that Linux Mint is the easiest and fastest OS to get use to for first time users, it is built on UBUNTU distro so 99% of anything that would work on Ubuntu works on Linux Mint. I.e. Steam Game Client form Valve came out for Ubuntu but easily installed into Linux Mint as well.
If you are new to Linux I would Read This:
http://www.techradar.com/us/news/software/operating-systems/beginner-s-guide-to-linux-where-to-start-1066778
Then Go here:
http://www.linux.org/