SevenOfNine, if it's not too late please take a backup/image of your Win7 install before doing anything. If things go south you can go back to Win7 pretty quick with a backup/image to restore to.
I've upgraded 4 computers, 1 desktop, 3 laptops from Win7 Home and Pro to W10 without any issues, some users on tenforums
Windows 10 Forums swear by a clean install. I didn't want to reinstall/redownload programs and set up my computers again, that why I chose to do an upgrade.
A computer that has problems, maybe has been used by more than one person, and has various issues that have built up over the years, a clean install will definitely be the better choice. W10 won't fix issues, you'll continue having problems just upgrading over those issues. For myself I'm the only user on the desktop and one laptop, my wife is the only user on her two laptops, none had issues so IMO an upgrade was the better choice.
W10 is not bad OS, it's not Win7, or XP, it's W10, until the end of this month it's free

Take the plunge and upgrade, you can always go back using your backup/image. I've heard the "go back to previous OS" function in W10 doesn't always work as advertised so a backup/image is your best bet. Take a browse of the Windows 10 forum to see what's being said and some of the posts, pretty much the same thing that goes on in this forum.
I don't really notice any difference between the two OS's. Take a backup/image of your existing Win7 install using either the embedded backup function, or a third party program such as Macrium Reflect. I've used the embedded backup for years, still works fine with W10 too.