When you want to watch a movie, which streaming service truly delivers?

If you want quality, opt for Netflix. If you prefer quantity, peruse Amazon Prime Video.

That's the conclusion from Streaming Observer. The tech news website looked at all of the movies on Netflix, Amazon, Hulu and HBO Now as of January 20 and analyzed the films' ratings on movie and TV review site Rotten Tomatoes. Also factored in: data from the streaming providers, as well as third-party search sites Reelgood and JustWatch.

The site found Amazon had the most movies (17,461) – four times that of Netflix (3,839) and many more times the amount on Hulu (2,336) and HBO (815).

But Netflix had more movies – 596, more than 15 percent of its library – with a "Certified Fresh" rating from Rotten Tomatoes, a designation given to the best-reviewed films.

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Amazon had 232 "Certified Fresh" films (1.3 percent of its library); Hulu had 223, or 9.6 percent; and HBO Now, 38, or 4.7 percent, Streaming Observer found.

Among Netflix's current cinematic stash: "Black Panther" with a Rotten Tomatoes rating of 97 out of 100; and "Raiders of the Lost Ark" rated 95.

Coming Wednesday to Netflix: "Incredibles 2."

Among Amazon's library are "Leave No Trace" with a 100 rating and "Lady Bird" with a 99.

Examples on Hulu include "Arrival" (94) and "Little Miss Sunshine" (91), and on HBO: "The Shape of Water" (92) and "Maria Full of Grace" (97).

While there's some concern about Netflix focusing on original content and "losing too many movies, one thing is clear – when it comes to the quality of its movie library, it’s still comfortably in the lead," said Chris Brantner, founder and editor-in-chief of Streaming Observer, in his post about the findings.

"In fact, Netflix has more Certified Fresh movies than Prime, Hulu, and HBO combined," he said.

However, Amazon's "large, diverse library," Brantner said, gives subscribers "plenty of options to choose from."

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Follow USA TODAY reporter Mike Snider on Twitter: @MikeSnider.

