I recall vaguely seeing the TV mini-series adaptation in the 1980s, though aside from the obvious I couldn't remember the plot. When I saw this in the Oxfam bookshop I decided - despite its author - to give it a try.
I think there's a reasonable story in the book - essentially a romance, with sinister foreigners, gladiators and Christians thrown in for good measure - though it isn't particularly well told. One assumes that Bulwer-Lytton did not obtain his honour for services to literature. Perhaps partly I am being unfair as I am unused to reading more historically written works - apparently this dates from 1834. I do, however, particularly dislike his occasional flitting between 79AD and the "present", and there's an awful lot of "canst thou/dost thou"-type speech, which may have been written with the intent of appearing archaic, but doesn't work because it's not actually of the period either. Also, I would have thought it was incorrect for the characters to refer to "the volcano" - they didn't know what it was. And then there's the generically verbose and florid style.