1.  You can install it side by side with Visual Studio 2005 without problems.

2. It has proper uninstall support so you can uninstall it next February when the new CTP hits the wire.

3. It adds .Net framework 2 SP 1.

4. There is a bug in the IDE that prevents you to view any RESC file. Right now you cannot  edit your project settings from the IDE (it will create a windows.shell.createpane() error)

5. To use LINQ or the Func<> delegates, you must link manually to the System.Core assembly which is located under c:\\windows\microsoft.net\3.5(something). The LINQ library is not installed in GAC.