Any reason why you want an apartment?
If you have an OTP apartment as your only option, here is my advice:
Personally, I would contact the developers direct and ask for cash back at settlement. Avoid going to a project marketer and DON’T pay the list price. Look for a project that is unique and not just a box. When I say unique, it must have guaranteed uninterrupted views of the ocean or river and no other apartments that can build in the same location. There are a few current projects in Perth which spring to mind, an old example is Raffles.
The two iSpire and Zenith apartments on the website of the project marketer of the Seminar you are going to DON’T look like good investments.
Feel free to PM me for more info on apartments.