I agree with
@juhful.
Windows 10 has not been yet released. Should you choose Windows 10, expect the possibility of bugs. Right now, I am running the Technical Preview (64-bit on my main system) for testing purposes, and for me it appears to be quite stable, however I am yet to find bugs on this build (for me everything is OK which I need to use).
I recommend sticking to Windows 8 and installing Windows 10 in a Virtual Machine. Unless you would like to take the risks of potential bugs on a unfinished Operating System.
You could always dual-boot Windows 8 and Windows 10 so you can use Windows 8 for work-related things (since Windows 8 is released and Windows 10 is not complete) and use Windows 10 for testing purposes, exploration of the new Operating System as it continues in it's fine development?
Personally, I think Windows 10 is already great and I am loving the work Microsoft have been doing for the OS. However, Windows 10 simply is not yet complete which is why I recommend to stick to Windows 8 until it is. Windows 10 will be free for you if you stick to Windows 8 for the upgrade when it's finished to be used, so you could always wait to use it when it's stable.
Cheers.