Oh he is not a good author by any stretch. The sci-fi equivalent of eating sugar - technically reading, has that fun sci-fi bits, but nothing of real value underneath.
C.S. Friedman is a highly undervalued SciFi/Fantasy writer IMO, I think she played in a lot of the same themes as Hubbard but with way better writing and much more interesting stories.
Hubbard was good at churn and rock solid as a swindler, and Mission Earth IMO was just him throwing his last "screw you"s to the people he conned.
A stupid but moderately entertaining read, with insane alien sex scenes, mostly from the perspective of a (I swear I’m not joking) small dicked trickster alien who keeps screwing up his own plans. I think its Hubbard’s self insert.
I wouldn’t bother with it though.
I see you’ve met my moron of an uncle. Who is in his late 50’s.