The xbox UI is the Yahoo Search of game console UIs. Full of noise that damn near everyone hates, as is evident by them changing it dramatically a few months back. Not much better now but at least I only spend about 10 seconds in the UI before the game loads.
The PS4 UI is just the 360 interface minus all the fisher price colors.
Yeah they fucked up when they made the One UI. I don't know why they think tiles is such a good thing to get to where I want to go. One big tile, and two smaller tiles, below it. Some ads in my face. Too convoluted, slow and messy. I heard they changed it now to be less messy but I haven't turned it on to update it.
PS4 UI is clean and simple. Get me to where I want to go. Store on far left. Library on far right. More recent things in the middle. No tabbing, or pages to flip through. I got a Pro already so no reason to drop $500 on the One X. I wouldn't have gotten one over the Pro anyway (for some stupid reason MS doesn't allow local backup of gamesaves which I desire, and I'm already too deep in the PS4 ecosystem, e.g. exclusives, trophies, etc)
MS is still holding strong with it's own dedicated base tho. I realized this when my stupid cousin who already owns PS4 wants to buy an Xbox just to play with his buddies. I told him to convince them to get on PS4 instead.