Kinda depends, they both seem to have similar specs, compare the prices of them too, one might be that much less money to justify getting it over the other.
But it mosty comes down to personal preference in this case. I should also say that I have no experience with the Sharkoon brand whatsoever but I know that Fractal has a nice reputation for good airflow.
Like I said though. Personal preference, and look up a few reviews on both cases to make a more informed decision.