I've never tried Grange myself and would love to just to say I have. I know enough about wine to know what I like but not much more.
However, my BIL in Tyson Stelzer who is becoming a very well-known Australian wine writer who comes from a teaching and science background. I don't mean that to sound like name dropping (even though I know it does) but more of a qualifier for something I learned from him recently:
If you use the most expensive grapes, from the most expensive regions and produce wine using the most expensive processes and bottle it in the most expensive bottles currently available; cost price=$22/bottle. (that is probably Australian industry only, I forgot to clarify with him) Whether it is any good or not will still remain to be seen so anything over that is name (and I guess that comes from consistency of taste/quality).
I've heard some people say that wines like Grange and Hill of Grace etc are nothing to write home about while others rave about them.
I say crack it and find out!

but make sure you let it breathe for a while before you drink it!!!
Cheers!
Jono.