One massive issue with the Xbone is that much more of the RAM is put aside for the operating system than the PS4 does. The Xbone is behaving a lot like Windows 8 in that there are tiles, and once you open stuff like settings, friends lists, games and apps tabs, and then a game, all those processes remain active until you manually close them. While it has memory set aside to do these things it seems like a waste and surely sucks some performance power from the games. There PS4 behaves like the PS3 in that trophies, friends, parties etc are built into the dashboard so you won't be opening a new tile/tab, and if you want to start another process it won't let you unless you close the game or whatever it is you are doing.
Physically the Xbone is a monster, about as big as an old school VHS player. Microsoft aren't taking any chances this time an entire half of the top of the case is set aside for cooling and there are large vents all along the side. In my man cave my Xbone sits on a table next to the TV, I don't think I would like to chuck it in an enclosed slot like in an entertainment unit. The PS4 on the other hand is slimmer and feels a little more robust. The PS4 can be put vertical with a stand and saves a lot of space. A mate at work isn't a massive gamer but likes to play, but he uses his Xbone as his media hub, connected to his computer and an external drive to play movies and stuff and by the sounds of it does the job pretty well.
At this stage if I had to recommend one over the other I think I would have to say the PS4. Like their new motto says, it really does seem more "for the gamers." But if you got an Xbone honestly it's never ever going to ever be a problem or seem underwhelming. For anyone that doesn't care either or, then just decide with your wallet.