>Again, it depends on what you are doing. If you are distributing apps that target the .Net Framework 4, then yes, it is beta and the customer should be told it's beta. If the customer wants to use new features, then they should be aware it's beta.
>
>If you're just using VS2010 and targeting .Net Framework 3.5 or earlier, there is nothing beta the customer is using.

FWIW, VS 2010 is leaps and bounds ahead of VS2008 if you want to learn Silverlight (and WPF) development visually. The XAML designer surface gives you instant feedback on how things are going to look, as well as allow you to drag adrop controls etc. without having to do the old code-run-see-code-run-see carousel. This effectively takes the somewhat mind-boggling Blend out of the picture, too, which is s good thing (unless you are a designer, of course.) After switching to VS2010 my learning speed has more than tripled because I don't get tripped up by silly visual stuff -- I can concentrate on coding business models and fixing those types of problems rather than messing with "imaginary design surfaces" while typing XAML code.

So, for learners that are planning to take time to get comfortable with VS over the next few months before putting anything into production, it probably makes sense to jump directly to VS2010 to keep the frustration level as low as possible.

Pertti