I can't see this in Australia but this isn't necessarily worse than seeing competitors in the 7-pack. Our Place Pages aren't as feature rich.
If I search for US plumbers in a random place, I see a "Related Maps" with a list of remodeling and repair services nearby. In other listings I see the "Nearby Places You Might Like".
I don't think it is accurate or useful. For example, I looked via the G Maps page for plumbers Delray Beach FL. The initial list shows plumbers in that locality. However, if I pick one and view its Place Page but not like the looks of the business, the list of plumbers in Nearby Places isn't useful, as it omits the others in the same locality but instead shows towns not immediately adjacent to that locality.
Perhaps this has some merit for tourism searches, e.g. picnic spots but now I can't (always) see the Nearby Places :(
anallawalla, the "feature" is very new, thus far, so perhaps it hasn't yet been rolled out to Google's non-domestic Maps properties.
Others of us have also observed the mystifying lack of consistency and relevancy for various Place pages.
It seems to me to be a very mixed message to try to persuade businesses to claim their place pages in order to add/update/control content upon them, and then to turn around and plaster competitors on the same page...
From a usability standpoint, I would think users could click on linked Business Category names or click breadcrumb navigation or the Back key in order to see other similar businesses in the area...