I am currently testing Windows 10 out. Right now, there is only a beta (technical preview) available. Proper software design goes through several stages of development. Alpha is the first stage and that is internal testing and design. Beta is the second stage and that is when the program is given to other people to test it out and, sometimes, suggest ways to improve. Release candidate is the final testing stage and this is when the program is almost finished but the developer wants to root out bugs; no major design changes will no occur. Finally there is release-to-manufacturing (RTM) when the developer is satisfied there are no more major bugs. Windows 10 is still in beta. When it is finalized, I will update this post. The last edit was 5/31/2015.
The official launch date has been announced: July 29, 2015.
But first, my early impressions.