Cabernet/Shiraz is Australia's signature blend. It works well. The structure of Cabernet is filled out by fleshy Shiraz. I think this would be a far more popular blend if regulation would allow it in the old world countries, for example in the Bordeaux or Rhone regions. However, over the last 20 years, this blend lost its importance in Australia, as the desire for pure varietal wines took over. Some companies have stuck with this blend, for example Yalumba. However, I detect new interest in it recently.
Tahbilk, who released the first estate grown Cabernet/Shiraz in 1972 has just reintroduced the blend with the 2010 Tahbilk Old Vines Cabernet Shiraz. The wine has a slightly fruity core of plum and blackcurrant. Vanilla from oak is quite noticeable, too. The wine is well balanced and flows seamless down the palate. This full-bodied wine produces a pleasant mouthfeel, which is not overpowering. It finishes with firm tannins.
A different beast is the 2010 Son of Eden Pumpa from Eden Valley. A super full-bodied wine with black fruit characters, this wine is jammy and it has chocolate on the palate as well. The wine is well made, but I find it too full-on. The fruit is from young vines and the wine is not expensive, but I cannot drink more than one glass.