I have a Silvia/Mazzer combo.
I managed to pick up a second-hand Mazzer (ex-cafe) for $225, using the Trading Post. I was very lucky in getting such a great deal. The Mazzer is a truly spectacular grinder. You can easily change grind setting b/w Espresso and Plunger without an "adaptation" period that I hear happens with other grinders. The grinder responds to change immediately without any wastage of coffee. It is also extremely quick, I can grind a double-shot within seconds.
I strongly recommend the Mazzer, if you can get a good deal. The Silvia is a brilliant machine, without any upper limit to espresso quality. The only variable is your skill level, which will improve over time.