I don't recall "Battlefield Earth " having a high audience rating response. I have never been able to sit through a minute and a half of it. Who the heck is "Johnny Goodboy Tyler?" And why do you know anything about the insane L. Ron Hubbard's writing style?
I suspect the truth is that you have read L. Ron Hubbard's works more than you will ever admit, but have never read Ayn Rand's work. I recommend "Anthem" first, then "We the Living" to introduce her background before you try the thicker books.
I could not get through a page or two of Dianetics back in the Sixties, and that was back before Scientology was understood to be a lobotomized idiot cult. His supposed Science Fiction was to arcane and boring to even open a book.
I was forced to read "Anthem" out loud for several weeks as a high school English class assignment, and my reaction to the novel was the way you describe "Dianetics". Her writing style was extremely grating and her characters were all one-dimensional people whose only purpose was to convey her message. The novel was very boring and predictable, no memorial scenes come to mind. Around page 3, I pretty much got the premise that there is no individualism in the future society she described and that the word "I" was forbidden, but Rand continued to beat the reader over the idea with this concept about five times every day, with her characters giving droning monologues referring to themselves as "we" over and over again.
Dystopian sci-fi novels about a oppressive totalitarian future society are a dime a dozen (and that was the case even in Rand's heyday back in the 40s!), and other writers have done a much better of conveying the same concept she had. Perhaps that's why everyone remembers Orwell's "Big Brother is Watching You" even if they haven't read 1984, but nobody knows about "Equality 7-2521" except hard-core Rand fans and people like me who were forced to read the book.
It's amusing that Rand's fans have accused me of being biased against her because she's an atheist, since I didn't discover her views on religion until years later, nor did I realize she had a rabid cult of worshipers who insist her books should be "requiring reading" (which in my case, it certainly was!) until years later. I judged Rand's writing abilities solely on the content of the book itself. Given what I read, I completely reject the idea that she was some kind of masterful storyteller and brilliant visionary that everyone should listen to.