It's been several days since the first EAP build of upcoming TeamCity 6.0 is live.
The changes page pretty much describes it all.
Along with improvements like separate status for the builds that did not actually start the build process and agent-side Perforce checkout, there are new features like completely new runner for IntelliJ IDEA projects (supporting IDEA artifacts building) and build configurations' build queue priorities.
The last one has experimental status and we might rethink the approach based on your input. Please let us know how well it matches your needs and how easy you find it to use.
The EAP should be pretty stable as we run the trunk version of the server internally for quite a while already. However, as always please mind pre-beta state and experimental status for the new features. TeamCity 6.0 is planned for the end of this year, and we want to hear from you on the features so that we can rework or polish them to match our audience.
Sorry for the late announcement here, but it takes some time to keep up to the team's pace being on vacation :)