It is better than Battlefield 3 and the Medal of Honor games, but still really short and lame. The story is basically a mix of all the cool moments you saw in Call of Duty games, but watered down, and the ending is easily the most anticlimactic ending I can think of.
I'd say it's ok for wasting some time, but mostly only worth playing for the multiplayer unlocks.
It's more Arkham City, so if you expect innovation like the previous Arkham games you might be disappointed, but it's more awesome Batman gameplay that is worth checking out. At the very least, it's something to play until the next Rocksteady game, and gives us a good look at the Batman of the game universe. It is really cool that the animated, cinematic and comic universes are quite different.
Uncharted 4, as fun as Killzone: Shadow Fall looks, I think the Uncharted series is my absolute favorite PS franchise. Right now none of the launch titles make me want to get a PS4 or Xbone immediately, but an Uncharted game on launch would very much make me reconsider that.
For Xbone, I think a new franchise would help, right now Halo and Gears are a bit tiring, especially since their creators have passed off creation of games to other devs (Bungie to 343 for instance)
We're not saying ME3 is the better game necessarily, that depends on whether or not you played the first two.
If you haven't played Mass Effect 1 and 2, or at the very least Mass Effect 2, you are doing yourself a massive disservice by not playing the game the way it was meant to be played.
Assassin's Creed II on the other hand does a pretty good job of bringing you up to speed, so if you didn't play the first AC game it can still be recommended (though if you do play AC1 first you are rewarded with some references and interesting story stuff).
So yeah, play ME3 if you have a save file for previous ME games, if not go for ACII and wait until you can afford all the ME games at once.