Thomas Hardy's "The Mayor of Casterbridge" is a heartbreaker of a tragedy.
That said, I can kind of see where some consider "Jude" and "Tess of the D'Urbervilles" as Hardy's masterpieces and this not quite. Mayor involves the rise and fall of a man as seen through his relationship with several people--his wife, his rival, his mistress, his daughter. "Tess" and "Jude" are essentially triangles (Tess and the two men in her life, Jude and the two women in his) and for much of their lengths solitary journeys. The greatness of Hardy's prose seems to shine brightest with solitary journeys--with relationships there tends to be dialogue, and Hardy's dialogue doesn't seem to be his best strength.
And "Mayor's" plot has all kinds of convoluted developments--missed meetings and subterfuges and stolen letters and such--to achieve its undeniably moving conclusion, where the plot of "Jude" and "Tess" move with a kind of simple and natural inevitability.
Still, there's a lot of power to "Mayor"--the early part, most of all (of which Michael Winterbottom's "The Claim" retains the most of, now I can see why); the grandeur of Henchard, particularly after he's fallen; his relationship with Elizabeth May, that moment whe he realizes he's come to love someone who isn't truly his--some of these scenes are wonderfully realized. "Mayor" is moving, especially to fathers who have daughters; to men who feel family is at times a blessing, at times a burden; and to anyone and everyone who has ever loved someone and lost them.