The spider has no defense against CC. You need to stop comparing them. Go both and play "cycle summoner" with 1 point in warfare, pyro and scoundrel and 3 poly when that time comes.
What you do is summon the spider, use adrenaline/offering and combo it with enrage + haste + supercharge. Then summon the incarnate, buff it. Next skingraft then enrage, adrenaline and supercharge him for mad damage again. Bone widow is now off CD you can use it again.
As a summoner skin graft, enrage, haste and adrenaline ftw
You can combo that shit like hell.
