I've played both, but I own an Xbone.
If you want driving games, then the Xbone is the only choice. FH2 and FM2 are better than anything else out there right now. Project Cars is coming to both next year, and will probably be 1080/60 on PS4 and 900/60 on Xbone. In isolation, you'll never tell the difference.
PS4 is more powerful, no question. Is it that much more that it's blatantly obvious? Not unless you look at the numbers on Digital Foundry, or the odd occasion like with Tomb Raider, no.
XBL is a more robust system than PSN, but PSN gets you MUCH better free games than XBL.
MS are much better at OS updates than Sony. The Xbone OS is miles ahead of where it was last year, and wees all over the PS4 for media stuff.
Controllers are a personal thing. The PS4 has the touch pad and lights though, which is cool. I still prefer the Xbone pad, but they're both great. Separate feedback on the Xbone pads is nice.
In terms of other games, the PS4 has many more smaller indy games. A lot more. If that bothers you, then that's an easy choice.
Tbh, there's less in it now than there was a year ago. I'm much more comfortable with my choice now that I was, as the games have justified it for me. That said, if you only want to play the big AAA multiplats then definitely go for the PS4, as its graphically stronger. If you want racing games, or the cheaper console, get the Xbone.