I'm from Melbourne, Australia and I've seen a good few Aussies showing interest in DU.
Considering the servers have not been fully optimised for release nor for Australia I have been playing DU without any major issues. Do get the occasional waiting for server when mining but I expect that to be better once go further away from the major populated areas.
Although I am on fibre, so with anything less than fibre to the property you will suffer with latency and have more lag to deal with.
DU will be much similar to other single shard MMO games like Eve Online, I imagine they will have optimisations around auth, chat, read only replica servers closer to regions, but at the end it's always better to be closer to the mothership (main servers) than further away and us AU folks will always have it worse, not only because of our geographical location but also because of our shite internet infrastructure.
This will be more obvious when playing in PvP, where locking and damage is going to be calculated by a single server, the closer you are to that server the more of an advantage you will have.
I have had to leave a few fights in eve online, because of lag when it comes to 1k player battles and the lag I use to experience, especially the case when I wasn't on fibre internet.