Well, when selecting a cargo hauler, the way I see it you basically always want bigger/more shields.
Taurus has 2xS2, that's 1k hp/s regen overclocked (FR-series).
Railen has 2xS3, that's 13.5k hp/s regen overclocked (FR-series).
Let's say you're flying alone, and two pirate Cutlass Blacks show...