This is generally regarded as George Gissing's best novel. It certainly is a great novel, but what needs to be said is that Gissing wrote at least three great novels, all of which could stand as his "masterpiece".
I refer to THE ODD WOMEN and BORN IN EXILE. Both George Orwell, Gissing's champion, and Queenie Leavis, who had very different standards than Orwell, consider EXILE to be the masterpiece. This trio of masterpieces deserves a greater readership than they've had since they were first published.
Gissing was also a very good critic, though unfortunately he wrote only one book of lit crit, a study of Dickens that ranks with the best of Dickens criticism.
What's odd to me is that in the period of Gissing's general neglect, HENRY RYECROFT was thought to be the best of his books. In fact, I'd say it's one of his minor works, far behind other great reads like THE NETHER WORLD, DEMOS, IN THE YEAR OF JUBILEE, etc.
The standard criticism of Gissing was always that his prose was wooden. Anthony Powell, no slouch himself when it came to writing occasional lifeless sentences, accuses Gissing of this failing. It's true that he sometimes writes very badly (Orwell cites several examples in his essay on Gissing), but a novelist isn't a poet and bad patches of writing have very little to do with the greatness of a novel. If they did, who would read Dostoevsky or Zola?
I highly recommend NEW GRUB STREET as well as the other novels mentioned above and some of the others in Gissing's oeuvre. He's a writer who commands more attention than he's received.