Here are a few answers to some questions/known issues:

If you have previously installed VS 2010 Beta 2 on your computer you should use Add/Remove Programs (within Windows Control Panel) to remove VS 2010 Beta2 and .NET 4 Beta2 before installing the VS 2010 RC.  Note that VS 2010 RC can be installed on the same machine side-by-side with VS 2008 and VS 2005.

Silverlight 3 projects are supported with today’s VS 2010 RC build – however Silverlight 4 projects are not yet supported.  We will be adding VS 2010 RC support for SL4 with the next public Silverlight 4 drop. If you are doing active Silverlight 4 development today we recommend staying with the VS10 Beta 2 build for now.

We recently identified a crashing bug that can impact systems that have multi-touch and some screen-readers enabled.  We are working on a patch for people who are impacted by it.

We recently found an issue where project upgrades from VS 2008 can take a long time to complete if the project has .xsd files within them.  If you think VS is taking a long time on a project upgrade give it a few more minutes to complete before assuming it has hung – you might be running into this slow upgrade issue.  Note that once the project is upgraded the performance should return to normal. We are working to fix this with the final release.

Hope this helps,

Scott