I thought I'd give Windows 10 a try. All I had to do was hit the little icon that had appeared a while ago as it seems the bulk of the download had already arrived.I started a few minutes before 7pm.
At about 7:30pm it was more or less complete.
7:35pm Windows 'welcomes me back'! Not that I had gone anywhere' I'd 'sat back and relaxed' as the previous screens instructed!
A couple of minutes later the attractive new screen appears briefly. Note that the time was an hour and ten minutes out! That was a bit strange.
The pretty screen goes quickly though and a minute later I am reassured that whatever's happening won't take long.
It didn't. After 'taking care of things' at 7:39pm I was able to use the new system, basically carrying off where I'd left off with a few tasks, at 7:40pm. Say, at the outside, 45 minutes from start to finish. I was impressed and the appearance is attractive. You will want to adjust the colours of the small tiles that appear in the Start menu, probably getting rid of quite a few!
So far all my old programmes work fine, including Office 97!! Dreamweaver MX had a spot of bother closing but had worked fine and Task Manager soon shut it down for me.
Just one problem but I am not at all sure it was a Windows 10 thing. I rely on the Auto Back-up feature that used to be a Picasa thing and is now a Google Photos affair. I am pretty sure it stopped the day before in 8.1 as there were no back-ups of new photos transferred from my camera on 29th July morning. Strangely, some items I had used to illustrate a blog and some photos I'd put on Facebook were backed up! Very odd.
Being quite concerned I put a plea for help in various places but got no response. Eventually I spotted this evening a comment from someone on the Picasa users forum that Google Photos backup hadn't been working in Windows 10 so the guy had uninstalled them both and reinstalled them. It worked for him and it worked for me too. I had tried downloading the gphotosback-up_setup file with Picasa in place but that wouldn't even open and was declared 'incompatible' by Windows. Clearly the uninstall / reinstall is the key if you happen to get stuck too.
So all is well, so far. To be honest, I don't see much difference but I guess some improvements will emerge in due course. I haven't used Edge yet but am told that is quite a major improvement on the browser front. Cortana will speak to you if you have a microphone or just give you ideas for various queries. She does insist on Bing, though. I guess that's understandable.
If you're happy with 8.1 then stay with that for a while as there are bound to be several tweaks and updates during the first few months. It is a free upgrade for most Windows 7 or 8 users which I think is great but you have ages to take advantage of that. No hurry but also no major issues that I can see if you decide to go for it now.