The Visual Studio 2010 and .NET Framework 4 Release Candidate (RC) is available to MSDN subscribers on Monday, February 8th, with general availability on February 10th.
In last December, VS2010 and .NET Framework 4 RTM was delayed due to some performance and virtual memory usage of VS 2010 Beta 2. The RC has been improved and much responsive than its earlier releases. The goal has been achieved, why RC was announced. The primary motivation behind the Release Candidate is to get broad feedback on the performance and stability work done since the last public VS 2010 Beta 2 release.
Here is few useful links, it may interest of you.