PS3's UI was obvious. For videos, go the Video tab and scroll down the list. Same for games. For downloads, go to the internet. For a setting, go to Settings and scroll through the list. Want to set a custom wallpaper? View your image, press the options button, and select 'set as wallpaper' from the options. Or go to theme settings and pick a wallpaper from images on your HDD. Which you could download from the browser, intuitively. PS4 has more features so that adds complexity, but they aren't arranged in any meaningful way. As I say, I've had the thing some 18 months now and only just figured that I could find my downloads by going to Notifications and pressing Options to select Downloads. That's illogical. Downloads are a file operation associated with games or the network. Notifications are simple feedbacks for events and activities. They don't belong together other than a notification when a download is complete.
And as for setting the wallpaper, it turns out you can't on PS4. That's moronic. That's what Nintendo does. Sony and MS provided custom backdrops, but only MS has kept that feature. So you fumble away in the menus trying to find a way to change the wallpaper, knowing they're not intuitive so having to plod away through settings and options, to come up with nothing and have to go on the internet to learn that the feature doesn't exist.
Obviously some things are better. Parties and party chat is definitely great. But I do often end up going to menu instead of side menu and getting a little lost, though that's probably from lack of use and familiarity. However, overall the OS/interface structure is, IMHO, pants.
