I've had my console for about a week now so have had a chance to explore its features and play some games on it. So far I must say overall I have really enjoyed using it although it is not without some issues. I will list those firstly then end with what I've liked about it.
Cons:
Voice commands have been disabled until patched.
Sound is only stereo quality until patched.
HDMI pass through used for connecting the mysky decoder degraded signal quality. May be remedied using better quality cable but I haven't tried that yet. (Update: I've searched and found that the issue most likely is a result of games running at 60 hz but TV running at 50 hz. In the US TV is at 60 hz so is not an issue there but for us in NZ or people in the UK it will make image quality particularly for sports very poor which is what I noticed. This may get patched I hope but there is skepticism in peoples opinions about whether this would be possible. I would say this is the most significant issue I've found and is very disappointing considering it was a key selling point in their marketing campaign. Score gets a minus 1 for this lack of foresight from microsoft )
Switches accounts randomly if the camera detects another account holder in the room.
Its important to note that all these will likely be remedied in future patches. Although the signal quality loss of the mysky box running through the HDMI in is a concern as I was looking forward to that feature. Haven't looked into whether this is something everyone has had trouble with or not.
Also another is that the camera must be between at a height 2 foot and 6 foot. My entertainment cabinet under 2 foot so when I stand up it can not see all of me until I sit down.
Pros
Great games on Launch. Forza 5 is amazing and the feedback from the new controller is fantastic. You can feel every bump in the road, the wheels spinning and the car sliding out and losing grip. This game alone is enough to justify getting an xbox one. Killer Instinct free download is also a worthwhile play. Even though its only one character free I had a few hours of fun on this. Great to see this game upgraded to next gen.
The camera recognition is rather cool. It recognizes me and my girlfriend when we come into view had says hi. Very polite :).
Can control it with tablet or smart phone. This was a cool novelty we had a play around with. The biggest use I could see for this is using it for a key pad. I'm sure there's better uses but that was one I liked from the start.
Camera can read the download code bar codes. This is a very nice little feature. I hate entering codes for extra download content in games so I love this.
It runs very quietly
Very easy set up and I had none of the reported issues with the disc drive others have reported.
Menu navigation is very quick and simple.
Kinect fitness looks like a cool new feature and there's lots of free workouts with xbox live gold or if you don't want gold their are ones you can pay about $15 to download. I think with gold as well it applies to all household users to be able to use this feature. I will have xbox live gold but with this I'm pretty sure my girlfriend can do the gold free workouts on her account even though she doesn't.
They have a greater supply capacity over PS4 making it easier to get one and to get good bundle deals on them too. I've seen a few bundle deals for xbox one but none for PS4. This and better launch games was the deciding factor for me getting it in the first place. I will still get a PS4 once they become available so I can upgrade and play my PS3 copies of Ghosts and AC4 on it.
So to wrap it up overall I'm impressed with it and happy with the purchase. I would give it a 7 out of 10 so far with a bit of leniency on some of the issues I've encountered with it due them being mostly launch issues that will be dealt with in future patches. So while it is still a work in progress I give them credit for pushing the boundaries and trying to give us something uniquely new. If you are wanting this for the multimedia side of things I would suggest waiting till next year until the issues are sorted out. If your wanting it for the games I would say go for it. Forza is amazing and I had a chance to play Ryse and Dead Rising 3 at Armageddon and they were both alot of fun. Free Killer Instinct is also a nice bonus.