The benefits not in common between the two bloodlines are as follows:
Thing : Elemental(Fire) | Efreeti
Skill : No difference
Arcana : No difference
1st level Spell : Burning Hands(Orc also gives this one) | Enlarge Person
3rd level Spell : Protection From Energy | Fireball
4th level Spell : Elemental Body 1 | Wall Of Fire (Orc also gives this one)
5th level Spell : Elemental Body 2 | Persistent Image
6th level Spell : Elemental Body 3 | Planar Binding
7th level Spell : Elemental Body 4 | Plane Shift
8th level Spell : Summon Monster 8(fire elementals) | Giant Form 2
9th level Spell : Elemental Swarm | Wish
Of all these, Elemental Swarm is the only one not in the Sorcerer list to begin with.
Feats : No difference
9th level Spell-Like : Elemental Blast (gives vulnerability for 1 round) | Efreeti Form (giant form 1, but also gain heat)
20th level Spell-Like... Doesn't matter for PFS, but here it is anyway : Elemental Body (immunity to crits, sneak attacks, fire) | Power of Efreeti (fire immunity, limited wish 1/day, plane shift to/from plane of fire 1/day)
TL:DR | Go Elemental (Fire) for the access to a single spell (at 19) you wouldn't normally get, and the 9th level Elemental Blast to give things Vulnerability that fail their save.
Or go Efreeti for flavor, or if you want to play more of a gish.
