Basically No it changes nothing, You should use windows 7 thats all i can say
I disagree. I've been running Win 8 since the 8.0 developers preview and have had zero problems related to Windows with
any software I use, and in fact a 10-20% frame rate increase depending on the game I ran.
The only issue I've seen at all with modded Minecraft was when I loaded Java 1.8.25 and that (so far) has only been with DW20 1.7.10 v. 1.0.2 crashing to the desktop after initially creating a new world, but after that I just restart and the world loads and runs normally.
Windows 10 preview seemed to provide an even better environment at first, since I just updated my convertible laptop from Win7 to win10 directly and most of the drivers were kept, but the first update replaced the whole package and I lost both the touch screen and stylus operation as well as my biologic login (fingerprint scanner) due to the drivers no longer being supported or available from the original companies that provided them to HP
Oh, and modded MC wouldn't load on Win10 but they are concentrating on business aspects for win10 first, with the focus for entertainment development scheduled for Feb 2015. Also, the laptop only has 4GB ram which considering the suggested Java ram configuration for DW20 1.7.10 is perfectly understandable.