I tried to watch an episode of TG: Australia yesterday to fill the hole left by no new TG episode (plus no Dexter, Californication, Entourage, or new Simpsons). I watched the fifth episode, where they tested the R8 and 135i.
I found the Australian show to be complete and utter crap. Just awful. It's like they began with the boring American vision of a car show (think Motorweek or C&DTV) and tried to Top Gear-ize it with horrible results. They use a studio that looks identical to the original show, the same theme, and the same basic show layout, which if anything just emphasizes the lameness of it in comparison to the original. The hosts are completely annoying and witless, and, unlike TG, they just seem inclined to gush about every car (again, in kind of an American-car-show fashion).
Major thumbs-down from me, and Fifth Gear will have to remain my distant second favorite car show (love Tiff, tolerate Vicki, dislike Tom and HATE Jason).