Hello Nakata,
First of all, TeamCity provides you with continuous integration solution. I won't explain why someone will need this, the best explanation can be found in Martin Fowler's article:
http://www.martinfowler.com/articles/continuousIntegration.html Unlike other similar systems, TeamCity has several outstanding features, like running server-side inspections (and view results on the Web and in IntelliJ IDEA), possibility to configure code coverage (and view results on the Web and in IntelliJ IDEA), and
test your changes on build server without commiting them to VCS. When a test fails, TeamCity shows you the build where the test failed first time and which changes broke it. When you see a stacktrace from the test, you can open this stacktrace in your
IDE with a single mouse click.
TeamCity supports many build runners for
Java and .NET, several version control systems (and their list will grow).