Really depends on a country. Some countries have great films in Prime and some have very little interesting titles (excluding their exclusives). Netflix overall I think is better but then again, some countries have way better offers than others.
Here at the bottom you can pick a country and see what's available there.
As a quick example, Prime video has around 32000 movies/series in the US available and only around 5600 in Germany and Switzerland is around 4800.