Good, photo-realistic smartphone, but one thing I notice (that is common with many 3D models) is there are a lot of unnecessary sub-serf modifiers and combined meshes, which make it inefficient as a whole. The buttons and the frame are joined together as one mesh and in order to make the buttons smooth and round, you have to set the sub-serf modifier (for both the buttons and the frame) to 2, when 1 is more than enough for the frame. This means you have to subdivide the frame excessively in order to get the buttons to look nice. It also means you end up with a ton of extra vertices for the frame itself, making the object more high-poly than necessary. When you go to use an object like this in a larger scene, and if you don't keep things like this in check, Blender ends up crashing and many users (especially noobs) have no idea why. The rest of the meshes suffer from the same problem and there are also many unnecessary interior faces, that will never be shown in renders, that are getting subdivided as well. So, if you're trying to quickly make the phone look photorealistic for a render, you end up with about 600,000 vertices, when I was able to get it down to 250,000, while looking just as good, with little effort. So, spending a tad more time on it could likely get it around 200k fairly easily which is 1/3 as many vertices. That's a pretty huge reduction. Trying to add several objects that suffer from this same problem to your scene can quickly add up and cause negative performance issues, especially when you add in other similar oversights, like 4k materials when 1k would do. It makes it really difficult to create efficient scenes as a whole when these things aren't taken into consideration. I have relatively fast GPU/CPU/RAM/SSD and still quickly run into performance problems with these things (especially because I work on a 4k monitor. I can't imagine users with lesser systems who are trying to create similar scenes fairing any better. It is however to scale, which I was pleased to notice. All of the measurements are completely accurate, and when I looked up the dimensions on Google liked that everything was correct down to the millimeter. It's not my intention to single out this individual 3D artist, or this specific model, but more to encourage 3D artists in general to consider users who can't afford as good of computers, and do what they can to make shared objects as efficient as possible.

nice work