Yes, you do look a bit limited for choice there.

I don't know if TPG resells their ports through other ISPs.

One thing to consider is that Optus may put more ports in your exchange at some point, opening up other options for you. So you might want to consider "length of contract period" if/when you make a move, and avoid any two-year contracts.

I've also found the 2008 Whirlpool Survey results, to add to the others I linked to above. Useful sample size when finding out what others think of various ISPs.