all depends on what you are aiming to achieve.
http://galaxylegion.com/wiki/index.php/Mission_ChainsPvP
> silthion chain - gemini cannons
NPC
> zolazin chain - 2 NPC slots
> lazuli chain - 2 NPC slots
> sha'din chain - 2 NPC slots
planet production
> trellith chain - trellith ability
> litheor chain - deep-phase probes
> alarri chain - trade outpost intelligence
> uldrinan chain - uldri power nodes
> taltherian chain - arti production
> mylarai chain - mining production
> ctp engineering chain - sulcation portals (mining)
allies
>
vollir chain - sehrinDo this one first. All good mission chains are now available as daily missions, and Sehrin is an alli that ranks whenever you do a daily mission> alarri chain - trovar
> lutuma chain - oruas eye
> raix chain - kriell
scan
> sha'din chain - zortah's
> prejoran chain - prejor beacon sensor
> uldrinan chain - uldrinan henxicant
> titancore chain - titanproxies