Haydn isn't heard much these days. He has long been nicknamed "Papa" Haydn, and he does seem to be viewed as a lesser-talented contemporary of Mozart, someone who is primarily famous for being one of the better placeholders between Bach's death and Beethoven's rise. This is, of course, totally unfair. Haydn is a composer of unappreciated depth, which I think shines forth in this, his last symphony.
During the Classical era the symphony settled into pretty much the form in which it would exist for most of the coming hundred years, the efforts of composers like Berlioz aside: four movement works, sonata-allegro form in the first, and so on. Haydn was deeply prolific, as just his production of over a hundred symphonies attests. But the work itself is the thing, and it glows throughout with classical restraint and an almost folkish feel at times. Even some of Haydn's joking manner comes through, as the symphony opens with a minor key introduction before settling in to a cheerful major-key allegro.
It's particularly interesting, when I've been listening to so much Mahler, to go back and revisit the earlier days of the form that Mahler would stretch farther than nearly anyone else. Here is Haydn's 104th Symphony.