I stated this before and will do so again. At the end of the day it all comes down to the games and how they look and how they play. Up until now, there has been ONE show that has allowed people to play both consoles. I was one of those people that was able to play many games on both platforms. Some were played on the show floor, some behind closed doors as part of meetings.
Based on what I played and I stress this as my opinion, the Xbox One games seemed cleaner, running smoother and just overall looked better than anything on the PS4. Forza 5 was the only playable game that was running pure 1080p/60fps and it really showed it strengths because of that.
You all can take that for what you will, but like anything in this industry, it is going to come down to the games, not a spec sheet. While one on paper can mathematically be more powerful, when it comes to games that usually always tells a different story.
Just to be clear: Yes, I realize that E3 is not a great barometer because of how early games are and nothing shown/playable was anywhere near final. However, with that being said, right now that is the only comparison that can be made between the two consoles until another event is hosted that allows for people to play both systems again.