I just finished reading L. Ron Hubbard's Battlefield Earth for the 2nd or 3rd time since I first stumbled across a hardcopy in a remainder bin in Torrance, California, in the mid 1980's (it was published in 1982).
FWIW, I'm not an L. Ron Hubbard fan generally, but he was a noted "Golden Age" science fiction author with a penchant for exactly what BE is: fast-paced space opera. Battlefield Earth (not to be mistaken with the execrable movie of the same name which bears no resemblance to anything worthwhile) is really space opera / earth supremacy story written at a time decades after that subgenre had reached its peak.
I'm afraid it wears thinner with each reading, for both cultural and style reasons; it's written in a deliberately formulaic style in a breathless rush. While its rapid pacing is a definite plus, it doesn't lend itself to character building beyond that of the pasteboard figures my sister and I used to snip from the back of cereal boxes.
In summary, it's not the greatest of space opera. But it's not the worst -- and it's a great example of the subgenre. In this day and age, it's a bit like opening a time capsule.
BTW, I recommend "Astounding: John W. Campbell, Isaac Asimov, Robert A. Heinlein, L. Ron Hubbard, and the Golden Age of Science Fiction," by Alec Nevala-Lee, 2018. It does a great job of capturing that extraordinary time in the development of American "pop fiction," while also describing Hubbard's somewhat checkered past.