This post is a little late since the SDK was released about a week ago.  At PSC we have been using the Open XML SDK 2 since its earliest beta.  It is a very powerful tool for generating documents without using the Office DLLs.  It is also the main technology that I have been working with for the last six months.  I would suggest giving it a try. 

Stay tuned here.  In the near future I will be presenting at different locations on this and other document generation technologies.

Download the Open XML SDK here.