Node.js 0.8 is out. It is faster, more stable, has major improvements in the Cluster module, a new Domain module and a new build system that depends on GYP.
Performance benchmarks shared by the team show improvements of up to 200% in Node 0.8.0 over the last stable version 0.6.19 (node uses a versioning scheme where the odd versions are unstable). There are speed improvements in throughput as well as in read/writes. The node team notes that most of these are due to improvements in V8 -
They've (V8 team) been very responsive to the needs of the Node.js project. A lot of Node's success is due to being built on such a stellar VM.
The Cluster module sees several new features and existing features are now faster and more stable. Some features related to file descriptors, that were deprecated in 0.6, have been brought back in some or the other form. A new Domain module allows you to group multiple IO features and handle crashes more efficiently.
Node also gets a new build system, GYP. GYP generates Makefiles, Visual Studio project files or XCode files depending on the target and has also been adopted by V8 and Chrome recently. Node already used GYP to build on windows since 0.6 but used WAF elsewhere.
You can see the complete Change API change details on the node wiki and the release announcement on the nodejs blog. Also, note that the latest stable version is 0.8.1, which came out 4 days after 0.8.0 was released, with minor changes.