Champ with cavalier dedication, mature draft lizard.
Eidolon pros: dont take double damage from aoe, spellcasting, fire breathing
Eidolon cons: less hp, no "free" actions (tandems).
Cavalier pros: more hp, better attacks, better ac later due to feats, free action from mature.
Cavalier cons: takes dmg from aoe, will need to be given commands if need to double stride.
Imo action economy is better with cavalier, but summoner provides spell casting and versatily...
Im lost.
Should be fixed