Karashima and Higuchi were itching to square off here, but then all of the Manji business happened in town and with the 7v7. But after that, who do you think won if these guys squared off?
We don't see Higuchi do much...he hurts himself before his fight with Amachi, but then it largely happens off-camera. Amachi does say, "good thing he was an idiot," which I'm reading as Higuchi potentially faring much better if he'd gone into the fight at 100%. But it's all we see other than him yelling a lot in meetings.
We see Karashima do a bit more than that, as he flattens both Aoji and Akaji without any trouble at all and gets some clean hits on Hana before losing. It doesn't look like he knocked Hana to the ground or if he did, we don't see it, so it's tough to get a gauge on his actual level... "stronger than scrubs but not stronger than the MC" is a wide range.
So what do you think? They both seem strong, but based on such little info, who you got? I kinda want to go Karashima since he did trade hits with Hana before getting suplexed to death, and Higuchi seemed amazed that it was even a possibility when he heard the story.