Think of it on a scale of 1-10. High floor means it’s not a stinker, so worst ranking would be in the 4/10 - 5.5/10 range. Low ceiling means it’s not going to be an all-timer, so the best ranking would be in the 6/10 - 7.5/10 range. Basically you’ll never HATE it, but you’re also never going to LOVE it.
Think of it on a scale of 1-10. High floor means it’s not a stinker, so worst ranking would be in the 4/10 - 5.5/10 range. Low ceiling means it’s not going to be an all-timer, so the best ranking would be in the 6/10 - 7.5/10 range. Basically you’ll never HATE it, but you’re also never going to LOVE it.
Seems more like a description of the author than a particular book.