I have been fortunate enough to visit New Zealand and Australia's 'subs' as part of expedition teams.
In many ways the subantarctic is underrated compared to the Antarctic. The Subantarctic has a desolate windswept lonely feel, and there is where one can get a much higher diversity of penguins and other sea birds such as albatross and petrels.
Most tourists go on one of the many ships that go to the Falklands and South Georgia on the usual milk run. The Australian/New Zealand side is not as regularly visited as the South American side, due to the longer distances and inconvenience. This is a shame, however, as there are several species, including some endemics, that can not be seen unless you visit this region.