Overeem is definitely a monster and I am impressed but I wont say that he is without doubt the best K1 fighter.
He had a tough time against Tyrone Spong, I thought Overeem would demolish him easily but actually it was a good fight, Spong even won the 1st round.
Then he defeated a very damaged Sakhi and at the end an extremely damaged Aerts.
I would love to see again Overeem vs Gokhan Saki, but this time a free injury Saki, I actually think Saki would beat the Reem.
Badr Hari is still the best K1 fighter IMO, a 3rd match with Overeem would be very interesting.
But congratulations to Overeem, if he is not the best K1 fighter, he is for sure one of the best. I hope nobody ever again says that JDS would outstrike him.