I,ve been a member of "connect" for some years.
Your chances of being selected as a Beta tester for a major release are extremely slim. I think they throw darts at a wall with a scattering of applicants on it!
However, better a try than nothing. Through connect I was one of the "dart hits" and got selected for Vista Beta testing
A point here is that there are quite a few other Beta testing offers, for which you will get selected. I even had to reject a couple as I became overwhelmed. It is important to contribute feedback, so that you are noticed as being of use for future applications.