Okay, I'm one of 'the new maintainers', but to date there have not really been a lot of significant changes in the sense of "let's rewrite this entire section of the code". There have been fixes for specific problems, some of which have been floating around on the internet for some time and were simply waiting for an 'official' route into beamer.
That said, there is always a risk when you change a piece of code that there are other effects you didn't think of/test for. I know that at least one issue came up that way as a result of a fix I added to beamer. Of course, once this was reported I went back and thought again, but I'm not going to say that there are no problems lurking. I don't know exactly which version went into the DVD version of TeX Live 2010, so you may have to do an on-line update to get the version with all of these fixes sorted out.
I tend to 'suck it and see' with updates, but I realise that no everyone is in a position to take that attitude. Khaled's approach is a good one, but if you only want to know about beamer then you can grab the code directly from CTAN and put it into your local texmf directory. That will let you do testing on the update without any other changes. Then you can test knowing that reverting it is only a case of deleting the local installation of beamer.
What I would say is that, at least for me, beamer is working properly: I use it too, so if it was broken for me I'd be straight on to sorting it out. That's true of most packages from most developers: we also tend to be users of our own work.