bmillan01
The OG 10 is a good source for questions. And yes, this book is still relevant and good for study. With that said, there could be some overlap with it and the GMATPrep software. This could lead to a less accurate score and test experience. But since you already have the OG 10, you might as well finish it.
I realize that you mentioned "standard material only," but pike is correct to mention LSAT passages for practice. Consider those as well.
Yes I am using LSAT papers and I get most of RC passages correct but for some reason OG 10 is giving me the jitters. Maybe its just me. I might be the first one to be more comfortable with LSAT passages than GMAT Passages.
The reason why I said standard material is that I took a couple of Mocks which had ridiculous RC passages - too complicated, but my GMATPrep had 0 RC mistakes - no guesses. So guess I have to try harder with OG 10.