Tracking

Enhancers (low slot)
Tech II (5)- tracking speed bonus 9.5%, optimal range bonus 15%, fall-off bonus 30%
Domination (8)- tracking speed bonus 10%, optimal range bonus 15%, fall-off bonus 30%
Republic (8)- tracking speed bonus 10%, optimal range bonus 15%, fall-off bonus 30%

Links (mid slot)
Tech II (5)- tracking speed bonus 15%, optimal range bonus 7.5%, optimal range +6.5km
Fed Navy (5)- tracking speed bonus 17.5%, optimal range bonus 8%, optimal range +7.5km
Shadow Serpentis (8)- tracking speed bonus 17.5%, optimal range bonus 8%, optimal range +7.5km

Computers (mid slot)
Tech II (5)- tracking speed bonus 15%, optimal range bonus 7.5%, falloff bonus 15%
Fed Navy(8)- tracking speed bonus 17.5 ,optimal range bonus 8%, falloff bonus 16%
Shadow Serpentis (8) - tracking speed bonus 17.5, optimal 8%, fall off bonus 16%

Appears the difference between links and computers are in the optimal range bonus(links) v fall off(computers) bonus. The forums claim that hybrids are designed to act within their optimal whereas projectile are designed to act within their fall-off making links good for hybrids and computers good for projectile.Looking at the range on a Heavy Neutron Cannon II (Tech 2 BS grade blaster), I notice that a link would about double the base optimal (7.5km optimal + 6.5km + 7.5% = 15km but this depends on how the bonuses are added).
Then there are enhancers. These do something similar but by using up a low slot, a place often reserved for damage mods or armour tanking. So it comes down to replacing a magstab with an enhancer. Straight damage vs better range and tracking, instinctually I would put an enhancer on a long range boat (rail fit).

Later...
Turns out that links are designed to allow a ship to improve a different ship, ie a remote tracking improvement.