Voltaire employs his usual blend of wit, satire, and humor to both elevate the liberal institutions of England over the still feudal Ancient Regime of France while also gently mocking the English in turn. He candidly discusses:

Religion: he is strongly in favor of religious tolerance, very strong (comparatively, at least) in England compared to France, but pokes gentle fun at odd English sects like the Quakers.
Government: in which he deplores the aristocracy of France compared to the meritocracy of England.
Science: in which he has the most unmitigated praise for English scientists, mostly Newton.
Literature: in which Shakespeare is a slightly barbaric English version of Corneille - how culture and language colors our views!
And, lastly, a discussion(/repudiation) of some of Pascal's Pensees, in which he endeavors to defend the human race against Pascal's Jansenist/Calvinist despair at the depravity of human nature. Which seemed sort of out of place in a collection of writings(/propaganda) discussing England, but fits in well with his philosophy and may have also been inspired by the Calvinists of various stripes he saw in England.

All in all, it's an funny, insightful, and thoroughly Voltairian work.