Netflix or Prime Video?
Netflix has a lot more choice but is more expensive.
If the price is not relevant, prime video can't compete with Netflix. The only reason for Prime would be if they have a few films or series that you really want to see and the Net doesn't have.
But I would rather use the trial month for that.
In terms of the selection of films and series, then Netflix. Bigger and mMn better choices.
Personally, I think Netflix is better. The selection is simply bigger and on Prime Video you often have to pay extra for series or films, which makes it a lot more expensive.