The first template I created with build 10574 didn't seem to work as I expected. After creating and attaching a new VCS root I had to go back to the general settings and re-input all of the required info even though I'd already done it. I saw the same thing with build 10380. I haven't tried any builds in between, but assume it's the same. It's only a minor annoyance, so I didn't bother to create a bug report.. Steps I took:
1. Install TeamCity 5.0 EAP
2. Create a new project.
3. Create a new template.
4. Fill out general info.
5. Create and attach a new VCS root.
6. Select 'Chose Build Runner'.
I got an error (don't remember the exact wording) saying a name was required before continuing. It was refering to the name in General Settings. Also, when I finished creating the build configuration I ended up with an actual build config rather than a template.