As you can see, there's a clear increase in detail - especially with low light images. To me though, the differences weren't big enough. Even from Blu-Ray to 4k, the difference in detail is often negligible when they're created from the same master. Of course, streaming can vary a lot more and I'm sure there are worse examples from iTunes.
I decided to use the money I was going to spend on a standalone 4k player on more movies.
I found this album while I was trying to make my decision.
Harry Potter and the Philosophers Stone: iTunes 4K vs 4K Blu-Ray - Imgur
4K Blu Ray vs 4K Itunes : hometheater (reddit.com)
As you can see, there's a clear increase in detail - especially with low light images. To me though, the differences weren't big enough. Even from Blu-Ray to 4k, the difference in detail is often negligible when they're created from the same master. Of course, streaming can vary a lot more and I'm sure there are worse examples from iTunes.
I decided to use the money I was going to spend on a standalone 4k player on more movies.