Well, you can expect online places such as Ars Technica and PC World to give you all the technical details, as well as Microsoft's "Getting Started with Office" site, and of course the ubiquitous Mary Jo Foley, but I'll give you a little more user-friendly views on all of this in no particular order for my own pleasure as I do love my Microsoft Office at times.

First, what's this about being able to download and use MS Office 2013 365 on 5 different computers? Well, to begin with, Office 2013 is the installed version of Microsoft Office. Office 365 will be made available online. From PC World:

Purchase the traditional boxed copy of the software, and you get a license to install the software on one device. You can also use Office 365 on any computer or tablet, but that won't be very useful if you find yourself somewhere without your usual computer and without Internet access.

Buy a subscription to Office 365, and you get licenses to download and install Office 2013 on up to five devices (right now, the list of compatible devices is limited to PCs and tablets running Windows 7 or Windows 8, though Microsoft says Office 2013 for Mac will be available by the time the final software is released).

And, as with the boxed copy, you can stream Office 2013 to any PC or tablet running Windows 7 or Windows 8. Microsoft has not yet announced pricing for either product.

Now, what have I so far noticed - from having used Office 2013 on a Windows 7 Enterprise machine professionally for a few hours?

The icons look weird! I mean, the icons on the taskbar. Check this:

From left to right, that's Outlook, OneNote and Excel. Quite a difference. I'm still not used to them, but it'll come. Outlook used to be yellow, so it's all a stretch.

The user interface is very Metro to fit in with the entire visual Windows 8 concept. All things in MS Office 2013 are decidedly white, which I quite dislike as I prefer my eyes to ease off the white intensity; in Office 2007/2010, you can change the colour scheme to dark which I've always preferred.

Here's a screenshot from OneNote 2010 to show you what I mean, with the black colour scheme enabled:

Here's the same bit in OneNote 2013:

If you ask me, I like darkness. Darkness! And I don't like the capital letters in the tabs, it's all a bit like shouting to me. And yes, the Share-tab is gone.

So, what about the theme? Here's what you can set, which affects the top right-hand corner of your Office applications:

Now, having set this to "Cloud", here you go:

How lovely.

Please do note the smiley in the top right corner of the screen, which is apparent in every Office 2013 application; it's there for reason. Click it to send the MS Office team a smile or a frown, which is Microsoft-speak for either reporting something you like about the system, a bug report or just a comment on something good or bad. It's all for the best of their product, which is why we're so graciously allowed to preview Office 2013 for free.

When starting one of the Office apps for the first time, you get to choose which to be the default: Office Open XML formats or OpenDocument formats:

...and you can insert "online pictures" through some of the apps:

...which looks like this, for instance, if you have integrated your flickr account:

You can also insert YouTube videos straight through a button under the INSERT tab, which is cool. Just paste the embed code and you're off. Otherwise you can search Bing Videos to try and find what you're searching for.

Speaking of integration, if you connect social networking accounts like LinkedIn with Outlook, you can search and see them live in your list:

So, anything else that's changed or is new?

Yes. A lot.

Typing in a new e-mail in Outlook makes the text flow, not appear b-i-t b-y b-i-t. It feels animated.

Word is now able to open and edit PDF-files. Sick! It does, however, not look exactly like the originals when you do open a PDF file, but it's a lot better than nothing. check if you're missing ms office 2019 keys or not.

PowerPoint sports a much-enhanced Presenter View.

You can see the weather inside of the Outlook Calendar, add different cities and switch between Celsius and Fahrenheit:

Microsoft Excel is apparently better to try and work out what you're aiming for to minimise manual work, calling this feature "Flash Fill".

Microsoft SkyDrive is now the default place to save your files, not your hard-drive, although you can still do both; SkyDrive offers 25 GB of free storage space and the ability to sync your cloud-based files to different devices.

Track Changes in Word looks a lot better, not swamping you with balloons everywhere.

A little tip: here you'll find proofing tools for Office 2013.

Of course there are snags. This is a preview, people! I've had problems with downloading templates to interoperability issues, but every time I've seen these, it's important to use the smiley in the top right corner of the screen, peeps! Otherwise, Bill G. might miss those things.

All in all: nice, but we'll see how it all pans out having used it more.

edit, 2012-07-18:

Wow: the built-in stationary from FrontPage 98 lives on in Outlook 2013:

edit #2, 2012-07-19:

I like the zoom feature in Word 2013:

edit #3, 2012-07-20:

Woo! Enter the 21st century! We're able to set an appointment as "Working Elsewhere", which I think is good. I mean, "Out of Office" could basically mean anything.

Speaking of Excel 2013, I just read that Neowin says the following about some AI:

Microsoft states Excel 2013 will offer users some more guidance in actually operating its many features. Microsoft says, "Features like Quick Analysis, Flash Fill, Chart Recommendations, and PivotTable Recommendations are examples of this type of guidance."

OneNote 2013 now lets you copy text not only from a page of the printout, but from all pages, and also lets you view an original printout, which means it'll try to open the printout in the associated application; this didn't work for me on a PDF which was sent from Outlook 2013 though.

edit #4, 2012-07-26:

I like the new threaded commenting in Word 2013:

edit #5, 2012-07-27:

MS Office 2013 applied some so-called Microsoft Office 2013 Click-to-Run Updates.

edit #6, 2012-07-30:

This wasn't very nice to see today, when starting OneNote 2013:

This is nice to see in Excel 2013 when starting up the app for the day, though, as the process was killed last time I ran it:

edit #7, 2012-08-01:

Today I noted the following when drag-and-dropping a PDF file into OneNote 2013:

Going for single creates a single page just as before. Going multiple creates one subpage per page in the PDF.

edit #8, 2012-08-07:

So, The Office Store has opened. All apps are - for now - available for free, but come launch date, it's pay for some.

Say you've added the Merriam-Webster app. What then, in Word 2013?

From within it, you may add applications through the web and see them listed in your Office apps. Just click through Insert: Apps for Office and there they are. for instance:

...and once you click it:

edit #9, 2013-08-08:

This is a bit of a menace, which I've reported to Microsoft:

edit #10, 2012-10-18:

In Outlook 2013, if you want to change the default action when replying to e-mails not to do this in-line, just open Outlook and click as follows:

File: Options: Mail: Replies and Forwards: Use inline replies when replying or forwarding.

edit #11, 2012-10-25:

In the final version of Office 2013, you can tweak what's included in the Ribbon, using Ribbon Display Options.

edit #12, 2012-11-08:

Woohoo! There are now - in the RTM version of Office 2013 - three different themes available! They are White, Light Gray and Dark Gray.

Here's White:

Here's Light Gray:

Here's Dark Gray:

edit #13, 2012-11-19:

In Word 2013, I just discovered the "pick up where you left off" functionality, which means that if you read a Word document, close it and open it again, you'll see a little pointer that allows you to go on and pick up reading/editing where you left off, like this: