The super, may be slower to fire, but it does have much more effective range. Normal one starts falling off at 4 tiles, 10 accuracy per tile. Super starts at 6, with 8 per tile.
With the better mode accuracy and better falloff the super has an effective range of about 10 for autofire and 12 for snap, while getting 100% shots. The sawed on the other hand is 4 for auto, and 7 for snap.
Also super has 6 gauge ammo with 4 more damage per pellet, and 15% better spread which further improves its outer range performance. Less pellets thou.