Being a Google Partner has many benefits, but they revise them all the time. Google seems to protect their intellectual property heavy, so as a partner, you can display their partnership logo to your potential clients.
Also, when they roll out new products in beta, you know before the public does. As Google products go, that's a huge benefit. They provide enhanced support when you need it as well.
I also do a lot of public speaking, so the one benefit public speakers enjoy is that they let you speak at their events; a very valuable benefit to us public speakers ;)
I hope this answers the question.