It is always possible that side-by-side installation issues exist, and you should have the appropriate safeguards in place (e.g. backup, use a VM, etc.).
In my personal experience, it has worked just fine. For my Tech Ed presentation, I rebuilt my laptop with Visual Studio 2005, 2008 and 2010 all installed side-by-side on Windows 7 x64. I didn't experience any problems.
The VS team has chimed in on this issue here. From the post:
"Q: Is it ‘safe’ to install VS 2010 Beta1 on my machine?
A: Yes! We’ve tested side-by-side scenarios, so installing the beta on a machine with VS 2008 installed is fine. The beta also supports uninstall and should leave VS 2008 and your machine in working order afterward. You can install VS 2010 Beta1 on a VPC if you prefer, though you will notice slower performance than if you run VS on your local machine. And please remember that however you install, this is pre-release software. The VS 2010 Beta1 readme documents major known issues, but it’s not guaranteed to be an exhaustive list."
I'd do it in a VM just to be safe, and so that I wouldn't have to uninstall it when the final version comes out. Also in the VM I could roll back to a clean OS and install RC versions. It's safer and you have more options in the VM, and I don't even notice the minor performance penalty. Someone go try it on their system and let us know.
It is always possible that side-by-side installation issues exist, and you should have the appropriate safeguards in place (e.g. backup, use a VM, etc.).
In my personal experience, it has worked just fine. For my Tech Ed presentation, I rebuilt my laptop with Visual Studio 2005, 2008 and 2010 all installed side-by-side on Windows 7 x64. I didn't experience any problems.
I have Visual Studio 2008 Professional SP1 and Visual Studio 2010 Team Suite installed on my Windows 7 box. I have had zero issues so far.
Does that mean you won't? I have no idea.
The VS team has chimed in on this issue here. From the post:
"Q: Is it ‘safe’ to install VS 2010 Beta1 on my machine?
A: Yes! We’ve tested side-by-side scenarios, so installing the beta on a machine with VS 2008 installed is fine. The beta also supports uninstall and should leave VS 2008 and your machine in working order afterward. You can install VS 2010 Beta1 on a VPC if you prefer, though you will notice slower performance than if you run VS on your local machine. And please remember that however you install, this is pre-release software. The VS 2010 Beta1 readme documents major known issues, but it’s not guaranteed to be an exhaustive list."
I'd do it in a VM just to be safe, and so that I wouldn't have to uninstall it when the final version comes out. Also in the VM I could roll back to a clean OS and install RC versions. It's safer and you have more options in the VM, and I don't even notice the minor performance penalty. Someone go try it on their system and let us know.