To be clear, my primary system is Win 7!
I have Linux Mint Cinnamon installed over Win 7 myself because once in awhile I still need the win 7 for one program. And hopefully I can also eliminate the need for that one soon.
But if I understood you correctly and you have an extra PC with the god awful Vista you are not doing anything with, it is the perfect opportunity and scenario for building a Linux Machine and give it a try! :)
I did it because us Win 7 users are going to get caught with our pants down here pretty soon, and I’m not going to do Win 10 EVER. lol
Trust me... The mint cinnamon is almost exactly like the Win 7 in feel and function. You will be cruising on it right away! Please just holler if you decide to do it and need any pointers!