The installation process seems to be pretty straight forward from both a clean install perspective or from an upgrade perspective (I used the Enterprise version, which allows an upgrade) and all in all took no longer than about 30 minutes on my X1 Carbon (8GB memory, SSD, Core i7)
Most things appear to work fine thus far, except installing my Fingerprint Reader (using the Windows 8.1 driver) crashes the login screen (where it flickers like crazy) so I am minus one fingerprint reader and had to do a System Restore.
So what are the obvious things that have changed?
The OS still looks very similar to Windows 8.1, however the Start Menu has made a return, and it's merged with the Start Screen, to put simply, you know have Live Tiles on the Start Menu (see below):
What also is new, is the ability to resize the "metro" apps and easily close them by clicking the X that we are all used to
Task View has also been added, given you a bunch of tiles with a tiny preview, allowing you to easily multitask. Personally I find this feature cool :) You can either bring it up by clicking the icon down in the task bar (pictured below) or swipe from the left.
The command prompt also has some changes, it now accepts short cut keys. I was able to paste in using Ctrl+V (rather than right-clicking) and likewise I was able to highlight and Ctrl+C to copy.
There is also a new Search box, which is available, by clicking the magnifying glass on the task bar. Like the Search on the old start screen, this will search the computer, web and show trending news:
A number of security features will be added too, although I don't believe these are part of the preview.
On top of BitLocker (which has been available in the Enterprise editions and some Premium editions of Windows Vista, 7, 8 & 8.1) Microsoft are adding additional protection using containers and data separation at the application/file level.
Microsoft are also enhancing security from an identity perspective, to improve resistance to breach, theft or phishing. This is done by easily integrating 2 factor authentication (such as smart cards and tokens)
Built in MDM capabilities will also be extended in Windows 10.
SCCM EndPoint Protection (as part of SCCM 2012 R2) also doesn't install, so I am relying on the built-in Windows Defender.
Other important apps I use seem to work fine, but I am sure I'll know over the next couple days whether anything else plays up.
From what I can tell, Microsoft will be releasing Windows 10 early next year. But in the mean time, have a play with 180 days technical preview: http://www.microsoft.com/en-us/evalcenter/evaluate-windows-technical-preview-for-enterprise