My suggestion is for you to try some of their other shiraz offerings. Try the Alices, Apricot Block, Creek Block and/or Seven Acre. I think they would all be in the same 'style' as the RR, although I have not had the RR to compare.
never underestimate the predictability of stupidity
For a fair comparison, I would suggest a wine similarly aged for an extended period of time. Try Dan Standish's The Standish, about $90?
The other wines suggested so far are big bodied wines but are in my mind quite different from the RR, and I think the oak treatment has something to do with this.