First appearance of Sentinels weren't so hardcore. They were destroyed via explosion. Even though they countered the original X-men's powers.
The original Manhunters were machines created by the Guardians of the Universe to police all the known space though they became equally insane and fundamental.
Depends on the Sentinal. The original Nimrod took out the Juggernaut in minutes and was preparing to kill him (somehow).
__________________ Land of the free, home of the brave...
Do you think we will ever be saved?
In this land of dreams find myself sober...
Wonder when will it'll all be over...
Living in a void when the void grows colder...
Wonder when it'll all be over?
Will you be laughing when it's over?
Fodder Sentinels go down. Bastion and Nimrod prove troublesome. Tri-Sentinel of Loki's imagination is also a beast.And Nimrod only took him down with sonics. No way he could have overcome Cytorrak's enchantment and killed him. Even D'spayre couldn't kill him after he'd drained all his power.
I say the more esoteric and unique Sentinel's win this for them.