Xbox One: Things I like
1. Friends
2. Games with Gold
3. Upcoming games (Halo, Gears, Forza, Sunset, Quantum Break, Fable, Phantom Dust, Crackdown, etc.....)
4. UI (The Layout is really great)
5. Kinect (Voice commands, and facial recognition are awesome features)
Xbox One: Things I don't like
1. UI (It can be a bit cumbersome to actually find something in the store)
2. Kinect ( The lack of any games for the device is a little disheartening, hopefully MS increases support)
3. Games ( Like most consoles in it's first year the games are lacking)
4. Controller feels cheap and not well made compared to Xbox 360
5. Lack of background/customization (There is a little bit, in which you can the color scheme of the dashboard. More is needed though).
PS4: Things I like
1. Consistent message and no back paddling on policies.
2. Upcoming Games ( Bloodborne, The Order, Uncharted 4, Ratchet and Clank, God of War, Tales of, etc...)
3. Controller (DS4 actually feels better than the Xbox One controller)
4. JRPGs will have a big presence on PS4 like previous Sony consoles
5. Better specs than Xbone
PS4: Things I don't like about PS4
1. Games (Like most consoles in there first year, games are lacking)
2. PS+ (So far only indie games have been given out, which with the exception of a select few I don't care for)
3. UI (The UI on the PS4 is very bland)
4. A lot of recycled content
5. Lack of customization for example Dynamic themes etc....
Wii U: Don't own yet so no comment.
Edit: Most of these things for both of them will be addressed in future updates, meaning most of the cons will no longer be valid with time.
