Hi Rick,
I have not installed any betas or RCs of VS 2010. Once the final version is released I will install it. If VS 2010 needs to upgrade the project and solution files it will be a pain in the arse much like we had when VS 2008 came out where I will have to make separate project and solution files for VS 2010 in order to keep support for VS 2008. If needed, I will do this as I definitely want to use VS 2010 when it comes out.
However, I think the more important question is when will we change the target platform to .NET 4 and I'm afraid that for an app such as mojoPortal with a lot of existing sites already deployed under .NET 3.5, as much as I'm eager to take advantage of new features in .NET 4, we cannot afford to be early adopters, we need to wait probably 1 year just as we waited a year to change the target from 2.0 .NET to 3.5 SP1. We have a lot of customers and cannot force them all to upgrade to .NET 4 immediately.
Best,
Joe