The all might Viscous fan

So I have a Flex fan right now that I want to get rid of because of what I Have read about it, So the Question I have is, is there a difference between the Mopar Viscous Fan and a Thermal and NoN thermal clutch driven fan. I want all the HP I can free up While not spending a Ton.

I have Heard that the Mopar fan is the best, But I heard it used a Thermal clutch. Then I heard that the Non Thermal clutch, the one that runs like a torque converter is the performance clutch of the two. SO what is the best one that will do a good job of cooling and free up the most HP.