I also find the products from the Penfold winery to be superior to those of Rosemount.
The quality of all low priced Australian wines has improved dramatically since the late 90s.
However, no sub $10 wine that I've tasted to date competes with the better $10 to $20 group. And, if you can find the Phelps for $8, as I've been able to do here in Chicago, it's hard to go back to the lower quality wines.
The Tranchero Cab, at a list price of $11, on sale for $10, is well worth the extra dolares.