I read
this yesterday, and though definitely biased towards Win7 some points do hit home (not specifically aimed at gaming, but it's a good read).
There's an interesting bit about how to get it free if Jim refuses your request (not tried it myself, so no idea if it works).
Quote:
Free upgrade to Windows 10 after July 29, 2016
How to save money and upgrade to Windows 10 for free after the free upgrade offer expires? Activate any assistive technology in your Windows 7/8.1, for instance, click + U and enable the onscreen keyboard and follow this link. I've just saved you up to $199.
I've been using 10 for a while now and I've not had any problems with gaming, though when I tried upgrading my wife's PC the ageing GPU wasn't detected and AMD don't provide legacy Win10 drivers so she was stuck with a weird non-native resolution for her monitor meaning I had to roll her back to Win7. I realise that's a pretty specific problem, but maybe something to be aware of if you're using some old kit.
EDITED: 5 Jan 2017 14:49 by GRAPHITONE