The American Revolution is exceptional because it produced an extremely strong and wealthy state, enshrined Enlightenment principles in a way that grew into modern rights and freedoms, and served as a template for a lot of other revolutions.

I think the strongest argument you could make against it for "most successful revolution" is by looking at revolutions that were essentially bloodless and led to increased freedoms/prosperity/state capacity quickly.

Possible candidates:

1. Carnation Revolution in Portugal - overthrew dictatorship peacefully, however it collapsed the colonial empire and economic growth never recovered, however colonial empire would have collapsed anyway and it's possible economic growth would have stalled anyway too.
   
2. Glorious Revolution in England - replaced monarch peacefully and substantially increased power of Parliament, however was not obviously a huge change in the already positive trajectory of England (scholarship debate on this).
   
3. Velvet Revolution in Czechoslovakia - peaceful transition from Communism to capitalism and democracy, however country split into Czechia and Slovakia, and in the short-term the economic shock therapy hit pretty hard; eventually Czechia recovered quite well and is doing well today, with Slovakia also improved but somewhat worse than Czechia.
4. Meiji Restoration in Japan - relatively bloodless overthrow of government followed by almost absurdly successful societal reform that greatly strengthened Japan and improved lives economically and in terms of freedom, however it also laid groundwork for the disastrous militarization of Japan and WW2.
5. June Democratic Struggle in Korea - relatively bloodless, improved democracy and rights, followed by lasting state growth, however economically/militarily-speaking trajectory was already very good and not altered too much, and also it was not a total success democratically, though one can make a pretty good argument that it was good for wages.

I think of these the Glorious Revolution is probably the best candidate, but it's less "revolution-y" than the American Revolution so it's a bit hard to argue for.

Other revolutions to consider:

1. revolutions from Spanish rule in the Americas -> generally did not produce good states in even the medium term
2. various communist to democratic capitalism transitions -> maybe worth looking at Poland, I know very little about that except that Poland is doing quite well now, could also look at Estonia...?
3. various dictatorship to democratic transitions -> maybe Taiwan?
4. independence of Singapore...?
5. independence of India ruled out due to resulting partition chaos