Copy and pasted from NeoGaf
PS3 has 960x720 resolution with QAA resulting in a soft look
Xbox 360 has native 720p along with 2x MSAA resulting in a far better IQ than PS3
The core artwork remains the same between both version of the game
Alpha buffers are rendered in a lower resolution on PS3
Xbox 360 has better AF and aggressive level of streaming compared to PS3
Game runs with unlocked frame rate and no vsync on both platforms
Cutscenes run with vsync engaged on both platforms
Xbox 360 version has the option to toggle Vsyn Off/On in Options menu
Digital Foundry:
It's rather unfortunate that the game is compromised by its technical failings on the consoles, in which some poor performance issues negatively impact the gameplay experience, with latency-heavy controls clearly compromising the fun whenever the engine is under load. In terms of overall consistency and performance, there's not much in it between the 360 and PS3 versions, though it's the Xbox 360 game that's the one to have if you're in the position of choosing between the two platforms owing to its resolution, image quality and streaming advantages. The action is a little smoother and the sharper image is definitely preferable this time around compared with the situation in Saints Row: The Third, where the softer nature of the PS3 release is joined with comparable performance to the 360, but without the screen tear.
That said, the console versions of Saints Row 4 fall well short compared to the PC game, where the opportunity for smoother and more stable frame-rates dramatically transforms the core gameplay experience, making it far more enjoyable as a result. The graphical upgrades in other areas might not be a colossal leap forward over the 360 game, but the combination of more refined visuals and better performance make it the preferred choice. The same holds true when running the game on reasonably low-spec machines, in which the ability to run at a solid 30fps in 720p or 1080p provides a similarly welcome upgrade over the console releases, even without achieving the aspirational 60fps experience that represents the minimal requirement for enthusiast PC gaming. PC should be first choice then, as you would expect at this late stage in the console cycle.
http://www.eurogamer.net/articles/digitalfoundry-saints-row-4-face-off
