I have windows 8.1, and can upgrade to 10. Before I do that, is there any reason for me not to do it?
No. In my opinion though windows 10 is better than 8.1. But not 7.
No. I like Windows 10 generally. The thing I don't like is the automatic updates. I can be a problem with a laptop when you have to leave an area. I had one mess up my system a few weeks ago and had to do a fresh install. Taught me a valuable lesson about backing up my data.