In addition to FreeBooter's excellent reply, I'd like to add my experiences installing Windows 10 on my everyday computer.
I have a Samsung NP780 laptop that came w/Win8
It had many, many problems installing Win8.1 - but it finally did about 5 months after it came out.
I upgraded to Win10 build 10060 (thereabouts) as my primary OS over a month or so ago.
Today my system updated to build 10130.
At first all was pretty good. I had one program that wasn't working - but I didn't use it often, so I haven't messed with it.
All my data was still there and it seems that all my programs are also.
BEWARE - this is an upgrade install, and they are notoriously flakey. I fully intend to do a clean install when Win10 is released (after backing up my data and downloading all the programs that I need).
EDIT: If you use Control Panel a lot, be aware that it's continuing to be deprecated. Settings is taking it's place. For example, you can no longer access Windows Updates by typing "wuapp" (without the quotes) into the Run dialog. And it's a pain to make shortcuts to it.
Recently my "SendTo" context menu has disappeared. I've started to research fixes for this, but nothing has worked so far.
It's a pain, but I don't use that portion of the right click menu that much.
Now I'm having issues with the main context menu when posting online.
The major problem is that it won't always show the proper entries - but one of them is an older program that launches out of the context menu, so it could be the source of that problem.
My Start Menu isn't very cooperative when I try to customize it. Again, it's not a major problem, so I don't mess with it.
I've got an icon in the System Tray for the Action Center - but it won't open anything (I think that it's not included in Win10).
The switchable graphics don't work for me (but that's OK as I had a problem with it before). It's actually better now, but I haven't played any games recently.
I just went to see if I could launch a game, and it seems that Steam doesn't see the games that I had installed previously - so those will have to be reinstalled.
Darned Edge (Project Spartan) keeps hijacking my default browser each time that I get a new build.
In short, if you're uncertain, wait until 29 July.
If you're concerned about performance, don't do an upgrade - a clean install is the way to go.
If you would rather just save everything, then do an upgrade - but don't say I didn't warn against it!
Edited by usasma, 02 June 2015 - 09:24 AM.