If you just missed out on the cut-off, I'd say usyd is easier, seeing as they take into account both your atar and gpa.
On the other hand, unsw pretty much gives anyone an opportunity to transfer into law, with people with 70 and 99 atars on an equal footing. Unsw also guarantees at least 100 law places for transfers.
I believe usyd says a 97+ atar and a D+ gpa should get you a transfer place, so with your atar you would be in a pretty good spot there. Nonetheless, a D+ average in unsw should also get you into law. I'd say go with whatever uni you like more.