Now that a confirmation of the NDA situation seems to be in place, let me shout from the top of the rooftop.

http://forums.create.msdn.com/forums/p/86027/517635.aspx#517635

Oh my goodness, WindowsPhone 7.5 Mango is SO GOOD.

1. Lock screen – now also shows music controls so you can fast-forward/back/stop playing current song without unlocking the screen.
2. Messaging – includes in addition to SMS, also Facebook and MSN Live messenger, you can also voice to text if you are driving
3. Mailboxes – linked mailboxes, threaded mail messages
4. Me – also includes Facebook notifications built in, also very handy to check replies to your Facebook or catch up on MSN messenger.
5. Zune – live podcast subscriptions over the air, this one is odd – you still seem to need to subscribe via Zune software, but once you’ve added a podcast you can download new episodes over the air to the phone.  Needs work – I can see big buttons for subscribe and settings – they are normally little picture icon buttons.
6. IE9 – holy it’s fast
7. Office – Skydrive and Office 365, WindowsPhone can always open and edit Office documents (Word, Excel, PowerPoint and OneNote), but now that they are all integrated with the cloud services this is awesome.  Lists, tasks in O365 also appears in the Office tab.
8. Background agents – available but nothing uses it yet
9. Live tiles – now with even more information (on the back) and most of the ones on your home screen are just bursting with more information.  But it’s still cute.
10. Multi-tasking.  It’s there, you don’t even know its there.
11. Bing search – visual, voice and location.  Location Scout actually has useful Australian local content.  Amazing.
12. Battery saver mode, actually the phone seems to be a lot better at handing battery.  I had a full charge from last night, and by the end of the day after decent use (no games though), it was still half a bar.
13. Voice turn by turn directions.
14. Camera – quick tab of screen to auto-focus and take picture
15. Power down – now there’s a cute confirmation screen when you try to turn the phone off.  On my HTC it was easy to accidentally bump the power button and discover my phone’s turned off.
16. People groups – when you add people to the default “Family” group, it automatically suggested contacts that has my surname (not common), and my wife, who didn’t share my surname.

Wish list

1. Still can’t take bloody screenshots from the phone :-(
2. When you are in a contextual hub, hitting the search button needs to be more intelligent. 
   1. In People hub, search people
   2. In office hub, search documents
   3. In Me hub, search people or text
   4. In Zune, search music in collection, swipe to market place
   5. In Mail, search mail