Star Trek fanboy here.
The Imperial Star Destroyer is fastest.
While the Galaxy Far Far Away's size is never concretely laid down anywhere, it's still a fucking galaxy, which makes it huge. Yet it can be traversed in a matter of hours or days at the most. There are various competing secondary sources as to exactly how long, but none of them posit that a Star Destroyer would take longer than a week to get from one side of the Galaxy to another. More to the point, Hyperspace can be used from within a star system, and computers exist that are both fast and accurate enough to allow ships to come out of hyperspace in orbit over a specific planet, or even IN ATMOSPHERE, as we saw in Episode VII.
As for the competition...
>MARS
Travel via Warp, assuming a "stable" journey, is much slower than Hyperspace travel. Even assuming no wibbly-wobbly shenanigans, it takes months or even years to cross the Milky Way. It's just plain slower.
Leaving aside the vagaries of Warp itself, the Mars-class suffers from the fact that Warp cannot be engaged within a star system, requiring both entry and exit near a system's periphery, and until then the starship is stuck at sublight speeds that mean that it can take days to travel from one side of a star system to another.
So the Mars-class must pick up the pizza, spend a few days getting to the system's edge, enter the Warp, travel through an explicitly slower FTL medium, exit at the other system's periphery, and spend a few more days reaching the end point.
>GALAXY
This is much easier. Maximum Warp Factor of the Galaxy-class is 9.8 ("Encounter at Farpoint), which using the TNG scale means that it can travel 120 light years in about 9.8 days.
anycalculator.com/warpcalculator.htm
(make sure to use the TNG scale).
However in actuality it takes more time because a Galaxy-class can't maintain maximum warp for days on end. Assuming a constant speed of warp 7, the trip is actually about 66.8 days.