I can't stand Apple so would not buy the box.The streamed 4k content I have is from Netflix which I know is 15mb/s so same as Apple TV. Its okay and I am quite happy to watch the odd film I would never buy as a disc and I watch all the 4k Marvel stuff but I can tell the difference when I put on a disc. I can even tell the difference between Force Awakes streamed v bluray. I just prefer films on disc. The sounds is a big one for me too since I upgraded my speakers I can really tell the difference when I see a 4k 5.1 film against a 4k Dolby Atmos/Dolby True HD/DTS HD. It may be more expensive on disc but I am picky over what I buy on disc. If I want to see a film but not buy the disc I`m still happy seeing it streamed HD. Just my personal preference.
Streamed 4k movies to me, and this is just my personal opinion so dont hate me but its a bit like having a 1080ti and your monitor is only 1080p 144mhz. You know what you are getting is smooth and looks good but there is still that nagging feeling you are missing out and should really be 1440p 144mhz. A bit like wanting a 1080ti but you have to settle for a 1070 as you really cant afford the 1080ti.
Full Fat disc is better.