Exciting news: Google Voice is now available to everyone. I was a Grand Central user since 2007 – before Google bought the company and turned the service into Google Voice. While I never switched to using Google Voice as my primary phone number, I still use the service extensively as my voicemail service.
Google Voice is fantastic for voicemail, since it transcribes your voicemails, allows you to forward those messages via email, allows you to set up different greetings for different people. If you want to learn more (and I suggest you do!) check out the Google Voice feature page, or watch the introduction video below.