The novel is about Candide, an extreme optimist who, along the journey, has his optimism worn down, until him and his friends find satisfaction in a simpler life.
The novel is very silly, a lot of good hoots to be had. The Old Woman With One Buttock and Martin the Philosopher are particularly funny sketches. Still, the characters are intentionally paper-thin plot devices.
Candide answered: —I have seen worse; but a wise man, who has since had the misfortune to be hanged, taught me that everything was marvelously well arranged. Troubles are just the shadows in a beautiful picture.
—Your hanged philosopher was joking, said Martin; the shadows are horrible ugly blots.
They make a trip to the legendary city of El Dorado, a utopia without suffering or conflict. That whole event was my favorite part. I think it's a statement about how people don't want what is good for them, even if it's right under their noses. They prefer the old way of life, to uphold old memories.
It's a fast paced book that doesn't take time to smell the roses. Voltaire writes like a scriptwriter, and a slurry of action inundates you. I'd say that the read itself isn't too bad. Since I read it in English instead of the French, it probably lost some flavor in translation.
Taken as a historical piece of fiction, it's insightful to study and you can tell the author is well read, but it's not a literary masterpiece. I think in an age where comedy standups and TV weren't as accessible as today, Voltaire filled the niche of a celebrity jester.