I rent and own investment properties and I haven't had any issues with PM's while looking for a place to rent. Most have been quite helpful ... even the assistants in their high heels.
Of course the agent trying to sell you a place is much nicer ... probably has something to do with the...
I just settled an apartment in Prahran a few months ago, and have used Jellis Craig. I was very impressed ... 1st IP so nothing to compare against, however I found them very helpful and have achieved higher rent than I expected, rented out by settlement date. Happy so far :)