So the Summoner is like an alternate Druid (animal companion)?
Final Fantasy type summoner. Bard like casting (up to 6th).
I assume Life link is not an action (just activates when needed).
Also summon spell SLAs as a standard action that last longer.
Merging is kinda cool as is Life Bond ("I can't die while my creature lives").
Only summoning 1/day of eidolon I see (though I guess it shouldn't die too often). Can't recall till next day (but can respec it every level of it abilities).
It has full BAB, Outsider HD, and 2 good saves.
Can the creature uses a weapon as a biped form? (oh I see they can since they can evolve to learn it).
Good spell list I think.
Overall, looks like a very interesting class, but lots of choices to look through to make the eidolon though.
Witch
Charm hex is save or successful diplomacy check... it is unique. Weird as I don't think of diplomacy as charm usually.
Evil Eye is weakens a thing (AC, attack, saves, etc). Decent as the save just reduces duration to 1 rd.
Healing limited to 1/day on each creature makes it kinda weak. I guess if no other healers in party.
Slumber- sleep spell single target.
Agony is pretty good.
Flight -minute/level each day is pretty low for out of combat, but useful in combat. Granted you could just cast the spell Fly as it is on their spell list.
Force Reincarnate is a save or die (didn't think one would see them in Pathfinder). Sure they get revived, but in a new body.