Here are the known issues in the new Windows 10 for phones 10051 build

[Windows Central]

The new Windows 10 for phones 10051 build is being launched today, but not without some known issues. Microsoft provided a list of the problems users might experience when they download and install the build.

Full story from the WindowsCentral blog...

 

[Guytronic]

Some important stuff missing.
No Office...no download

Actually I wouldn't risk it only having one Lumia phone at the moment.