As many of you know Microsoft announce the new RTM version of BizTalk 2013.
All of the most important new feature are listed in BizTalk Blog Team
The core topics are:
- Improved Performance
- Simplified Development and Management Experience
- Cloud Connectivity
- Running BizTalk Server in the cloud (IaaS)
- Support for the latest platform and standards
The most important for me and I think for a peoples that work in hard and deep with BizTalk are:
Ordered Send Port improvements, increasing performances
XslCompiledTransform, increasing performances
Host handler per adapter, good best scaling and for best dynamic scenarios
Notification Services for BAM alerting dropped! 
Dependency tracking, good for monitoring aspects
SFTP adapter, so we will have a BizTalk SFTP adapter in box
Licensing changed, all info in Saravana Blog