Old question - New to me 4/3 system

I read the 4/3 website. Don't understand it. And I asked "experts." There response is that the 4/3 system is a smaller sensor = more noise.

Let me ask you this, is 4/3 any good?

I was leaning toward a E500 until someone convinced me not to. Now I'm back. This is my first Oly question.

TIA