First off, I would point out that Peikoff's OPAR is a pretty advanced book that assumes thorough knowledge of Rand's fiction and non-fiction on the part of the reader. For this reason alone, it would be a poor introduction to the philosophy, even (or especially) for someone who had a fairly sophisticated knowledge of other philosophical systems.
Secondly, some of Peikoff's arguments seem pretty tangled, and in a few cases, such as his notorious discussion concerning the choice to live, seem to contradict well-known tenets of Objectivism. He wrote the book after Ayn Rand passed away, so it was never vetted by her for correctness.
I would recommend that you consider the philosophical aspects of _The Fountainhead_ and _Atlas Shrugged_ first, then read the major works of Rand's published non-fiction (such as _The Virtue of Selfishness_, _Capitalism: the Unknown Ideal_, _The Romantic Manifesto_, _Philosophy: Who Needs It?_, the title essay of _For the New Intellectual_, and, when you are ready for something really challenging, her _Introduction to Objectivist Epistemology_.)
The one thing that this approach to her ideas is missing is a sense of how developed Objectivism is as a _system_ of ideas. Rand states this repeatedly in her writings but, because most of her non-fiction is in the form of brief essays on particular topics, there is no single place where she lays out the whole system of her mature thought. For a survey of that, I would recommend the recorded lectures of Peikoff's _Introduction to Objectivism_ course, which was done during her lifetime and with her approval, and/or his _Understanding Objectivism_ course, which was done shortly after her death. I have not heard this last course myself, but it is almost universally praised as the best overview of her thought by those who have heard it.
If you were already familiar with her fiction, but wanted a brief intro to her system before plunging into her non-fiction, I would recommend Shawn Klein's 6-lecture intro course available from The Atlas Society's bookstore. While it is not as thorough and systematic as Peikoff's lecture courses mentioned above, its shorter length, budget pricing, and orientation to beginners make it a good choice to start out with.
Forgive me if I have underestimated your knowledge of the philosophy, but I have not seen any of your posts before and had to make a guess.