Mint is pretty user friendly and easy to set up
I was already using Libre Office so that was no problem. I'm using several computers - a PC on Win 7, a laptop on Win 7, a PC on Mint Cinnamon 19, and an android tablet. I also use P-cloud to swap files between them all.
What I haven't got used to is using Thunderbird rather than Outlook, and Gimp rather than Photoshop. And there are lots of little differences - Mint is more evolved than Win 7 with more options, so while everything can be done, it takes time to learn how.
I'd say days to be OK, but weeks to be fully at home. But I have been using 7 for about 10 years.
I'd go with this new update - you can test it from a boot CD but they only run properly once you install them on a solid state drive - so install on a spare drive for a proper test
https://www.linuxmint.com/rel_ulyana_cinnamon_whatsnew.php
My 'needs' on a comp are pretty narrow.
So now,I just need the balls to install it without worrying about fucking everything up!! lolol
Try is out on a spare hard drive - although if you have win 8 you have nothing to lose so might as well over-right it with mint - 8 is a joke