Well, the PSN launch on PS4 is officially a bust. The thing crashes more often right now than a PS3 trying to play Skyrim.
And I REALLY don't like how the PS4 hides your download history and makes it REALLY hard to find individual things you've purchased.
On the flipside, I REALLY like that the PS4 can download multiple files at once. ABOUT ****ING TIME, SONY!
One other thing, too: this UI is lightning fast. When I go to launch a game, I'm in the main menu within 1-2 seconds. It makes the Wii U's 12-15 seconds before loading into game look like even more of a joke. My big complaint about the UI is that there is no real way to organize anything. Seriously, what is with console manufacturers launching systems without folder support? The PS4 uses this increasingly long horizontal bar to show EVERY game you play or download all at once, and it gets longer with each game that's added. That's going to get incredibly unwieldy extremely quickly.
Update: OK, I like Sony, but the way they have the file management system setup on the PS4 is borderline shady. You don't have a download history anymore, and the PS4 does not report your downloads to the download history your PS3 or Vita can see. Instead, you have your "library", where everything you have downloaded or installed for a game is listed, but the UI is very vague about whether you have that currently installed or previously downloaded. The UI seems intentionally designed to hide information about what exactly you have on your HDD, actually. I know I downloaded updates, etc. for certain games, but it doesn't split that info up in the System menu.
Oh, and the PSN store still sucks ass, even if it does load extremely quickly now (and crash just as quickly). It's still a cluster**** to navigate.