Donne was a metaphysical poet. Critics (such as Pope and Samuel Johnson) used "metaphysical" in a derogatory way citing that Donne dealt too much in philosophical ideas and that his preoccupation with sex made his poetry lewd and not intellectually rigorous. Donne wrote often about love and how sex (physical) was an integral part in achieving transcendent or "holy" love. In other words, Donne did not think physical love was somehow inferior to a mental or philosophical state. So, Donne was all about the emotional and intellectual. “The Canonization” compares lovers and saints.
Pope was much more concerned with structure, morality, and cultural integrity; all written for an elite intellectual crowd. Pope was into deeper significance of human existence, but his poetry is not as philosophically wandering or as personal (subjective) as Donne’s, the metaphysical poets or the Romantics.
This is an oversimplification, but a starting point nonetheless; Pope is satiric, intellectually complex, precise and reasonable. Donne is personal, witty, satiric and spiritual.
Pope believed good poetry (aesthetics in general) tapped into timeless, universal values; The eternal is superior to the personal.
Donne saw poetry as a more subjective and individual practice.
This makes it sound like Donne was liberated and Pope was an uptight critic. To an extent, this is true but again, an oversimplification. Donne was deeply religious and Pope mocked classical epic.
Just look at titles of some of their works. Donne’s “The Flea” is a metaphysical conceit about sex. Pope’s “Essay on Criticism” is a long diatribe about poetry and criticism.