This can only appeal on a single dimension, really, and that is as a curiosity. There is no coherent plot, minimal characterization, and to call the style workmanlike is to go overboard with praise.
I chose to read this for a number of reasons. Harold Bloom of The Western Canon fame claimed a lifelong obsession with it. C.S. Lewis and J.R.R. Tolkien both claimed to be influenced by it. Horror writer Clive Barker called it a "masterpiece". Yet, I had never even heard of it. Also, its copyright is expired so it was free on Gutenberg.
We start with a seance and are introduced to a number of standard Edwardian British characters. One of the guests has invited a pair of strangers to join in. Then weird things start to happen which eventually end up with the two strangers and the medium taking a spaceship to Tormance, a planet circling the star Arcturus.
One of the strangers, Maskull, starts encountering the denizens of Tormance, each new encounter places Maskull in a strange new moral system. He immediately adapts to each one, his body literally transforming, as he moves seamlessly from total pacifist to murdering people with his mind, and various convoluted situations in between. I couldn't really follow the causal links because there weren't any that I could see.
In the end, Maskull appears to have come to the realization that all human morality is arbitrary, or at least no one moral system is provably better than others -- maybe. I'm not sure, and I don't think I'm supposed to be. The final actions are outright cryptic.
Should you read Voyage to Arcturus? No. It yields no particular rewards unless you have an interest in writerly techniques. It eschews most traditional qualities of good writing but does demonstrate how a reader can be drawn to see existential or spiritual concepts when confronted with an oblique, ambiguous, fantasy narrative. The tone was influential to writers mentioned above, who put it to use in more gratifying ways. Despite their praise, on its own merits, it's just a curiosity.
