A powerful rhombus, the Playstation 4 features the latest in gaming technology but few frills. If you're looking for something with a fast interface that is dedicated purely for gaming, this is your console.
Excluding gaming PCs, the Playstation 4 is the most powerful current console on the market and it shows. If you have a high-definition television, the differences between the PS3 and PS4 are astounding. Both the PS4 and Xbox One have plenty of untapped potential.
Now that I own both consoles and have spent enough time with them I can say, without a doubt, that the Playstation 4's UI is much faster and more responsive than the Xbox One. I'm not entirely sure why that is (it could be that the Kinect slows down the X1), but it's obvious enough that I have made it a point to use the PS4 for Netflix and any other non-gaming activity that I can.
This might seem trivial and/or obvious at first, but the PS4 versions of games is far superior to the PS3. Having played numerous titles on both the last gen and current gen consoles, I can honestly say that titles that straddle the line between the PS3/X360 and the PS4/X1 (i.e. Battlefield 4, CoD: Advanced Warfare) are far better on the newer platforms. I don't just mean that they look better, I mean that they are more responsive, more stable, and sometimes feature more content.
This might seem minimal to the casual observer, but once you notice how many ads riddle the Xbox 360 dashboard I consider this a plus. Fewer ads mean that there are fewer buttons for things I don't want and the things that I do want are closer to access. Aside from the store and the "what's new" page, I haven't found any ads in the PS4's dashboard.
I have a USB headset that I love. I can plug this headset right into the PS4 and begin using it immediately. I can't do that on the Xbox One. The PS4 also is far more likely to recognize video files that I have on external drives than the Xbox One.
This issue currently plagues both of the now "current gen" consoles, but it's still a serious problem. While I can (and do) make arguments that games are better on the new consoles when compared to the old consoles (see the left column on this page), there really isn't a long enough list of titles that would make me say with certainty that I would buy a PS4 purely based on the current crop of exclusive titles. Almost all of the best titles are out on another platform as well (usually PC, but plenty of titles on the X1 as well).
One issue I had with the Playstation 3, and something that continues to plague the Playstation 4, is that the UI is unbelievably disorganized. Instead of lumping installed games into an easy to access panel, the list is thrown down a horizontal bar of icons that includes everything the user has previously played, as well as categories for other apps (i.e. video/audio apps). Up until recently, the store was hidden on a separate horizontal section along with the settings, messages, and notifications. Setting up a party is not an intuitive process and doing something as simple as moving a video file onto an external drive can only be accomplished by navigating a confusing maze of icons.
I have an external capture device that I use to record long gameplay videos. However, because of built-in anti-piracy settings, I have to disable a setting every time I want to record any video with this device. Disabling the setting also prevents me from playing any movies or watching any streaming content (i.e. Netflix), so I have to turn the setting back on once I'm done recording. It's a slow process that does little to actually prevent piracy.
As much as people might complain about the Kinect, it does have some occasional usefulness and applications both within games and outside of them. However, the Playstation Camera is a completely underutilized but expensive device to the point where I can't think of a single reason why anyone should buy it.