Super speed also needs super durabilityThey have to come with the secondary abilities or they are useless.
Super strength needs the durability to not have your bones be broken lifting or punching stuff.
Super speed needs the increased perceptions, reaction time and reflexes to be to see and weave your way through things.
I'd choose super speed, it'd make me a bit smarter.

Omni-Man has invulnerability. Just super strength alone would get smacked by super speed.

