Sprint has said Possibly October but the info has leaked that it is Oct 19th... just so you have more specifics... that's a recent development.
It runs windows Mobile 6.1 which I have already upgraded my PPC-6700 to... I really haven't had an issue with anything not running.
There is also the touchflo 3D interface but the interface should not impact the way your software behaves.
The one thing I will say though is with the HTC home and Touchflo 3D and Windows 6.1 alot of what you think you need you might not need anymore... for instance weatherpanel... HTC home has a weather tab that seems to be OK... that's on my PPC-6700 also and I use it all the time.
Windows 6.1 Touchflo and HTC home will remove the need for such applications as "devstate" and some other apps that helped you close applications easier, end tasks and use shortcuts.
To be honest I don't install much on windows 6.1 with HTC home and some of the HTC apps ripped from the Diamond ROM.... there just isn't much need most of what I used on a daily basis was improved so much I quit using most 3rd party stuff.
All set to buy one myself once Oct 19th hits... going from PPC-6700 to this will be huge for me since I am skipping generations of improvements to features and performance even if I did end up using the same OS and some of the interface and apps on this.