SuSt with the SSF patch installed gives you all the extras then you get in SSF.

Things like -

1) Trucks can now pick up ammo crates.
2) Infantry can get ammo from the crates direct.
3) Units have both experience bars.
4) Vehicles reverse.
5) After installing the SSF patch, campaigns from SuSt when loaded will have all the features that SSF have, also some of the weapons will change in name and use.

6) Experience bar for each unit has two bars now one purple (units own experience), and one red (bonus experience), this only appears when the unit is near an officer and is only temporary.