Xbox One & PS4 wont b able to play there previous consoles counterpart games, the only console of the generation that supports this is the Wii-U, the Wii-U is also the only console to support the controllers from the previous console.
the bad features from the Xbox One r as follows...:
#Only supports HDMI output.
#Does not work unless Kinect is connected.
#Still payed online.
#Pay to play used/pre-owned games.
#All games need to b installed like a PC.
#Need to be connected to the internet daily.
basically as it stands it is between the Wii-U & the PS4, have to w8 on E3 to see if M4 has a gd comeback which is highly doubtful if they keep some of those stupid features mainly pay to play used games IMO, however all that being said, a lot of ppl will most likely buy the consoles after hackers/modders releases something to bypass all the BS.
http://www.youtube.com/watch?v=KbWgUO-Rqcw
http://i.minus.com/iBzvb2JSpQNRM.gif