What is it the Microsoft have done that is so revolutionary to gaming, please don't say motion controls as that's something that has been rejected by gamers.
In my opinion, the XB1 is more revolutionary in what a console brings to your living room, rather than what it does for gaming. Let's be honest here, in terms of actual gaming, both consoles are just more powerful versions of the previous generation. Neither one brings anything really revolutionary to the table in terms of how we play our games (considering Kinect and the PS Eye were available last gen as well).
I'd consider the XB1 to be more revolutionary than the PS4 simply because of the media side of things. I know we're lagging behind the US in terms of implementation, but the vision MS have shown is certainly a more rounded package than the PS offers, though of course the PS4 is simply a more powerful gaming machine.
The things I'm looking forward to trying are things like Snap, where I can do two things at once. That's pretty revolutionary for a console. Being able to Snap YouTube to watch a walkthrough of a section I may be struggling with, or browsing Netflix while doing something simple like scouring the transfer market in Fifa. These are features consoles have ever had before, and I can't wait to try them.
Of course, the PS4 does have some great features of it's own, and I'm very much looking forward to trying them. I'm not overly bothered by Gaikai simply because I'm not too bothered by the backwards compatibility features. I also have a relatively slow 6MB connection so any streaming gameplay wouldn't really be good for me. The 360 was BC with a number of games, and I think over the past 8 years I've used it twice. I do like the media sharing though, and I can't wait till I get my PS4 to try it out.
At least the differences between the consoles make it easier to make a choice. If all you want is the most powerful gaming console, get the PS4. If you want something a bit more rounded, at the expense of some power, get the XB1. It's as simple as that IMO.
Edit: One area where I will say the PS4 is way ahead is in terms of remote play via the Vita. That is a fabulous addition if it works properly. Of course, that drives the cost of the console up if you don't already have the Vita, but it's a brilliant feature.