From what I've seen, Battlefield 4 seems to be the one game that gets a huge upgrade in Xbox One (much better visuals, 64 player multi instead of 24).
What about games like CoD Ghosts, Assassin's Creed IV, Halo: Spartan Assault, Thief, PvZ: Garden Warfare, and everything else released for the console thus far? Is it worth buying the One for any of these? Or could I save more money getting them on the 360?
"Guess what?! I got a fever, and the only prescription... is MORE COWBELL!!!"
As one who has played both the 360 and One copies of Tomb Raider, Ghosts, and Battlefield 4, I can say that there is a big difference in all three of the games.
Haven't played any others on both systems, but I also have Thief for the Xbox One and it looks spectacular. I can't imagine it looks that good on the 360.
Ghosts is better on the 360, not that it is "Good" anywhere. You don't get the crisp textures but the maps load 3 times faster on the 360, and anywhere from 8,000-50,000 play on the X1 most of those are the corner camping DB's that will stay playing that same game sitting in that same corner until the next cookie cutter installment. I would be surprised to see more than 20,000 at peak times after Tuesday. TF will effectively kill Ghosts player count on the X1.
I'd say the one with the biggest difference between it's 360 counterpart is definitely Battlefield 4. I don't know if I'd call the graphical improvements in other games "negligible", but Battlefield 4 is literally night and day when the other games arguably are not.