I havent tried the fluval but my quiet one is awesome. thats my recommendation.
My eheim is good but it makes a weird noise on start up. not a huge deal but thats it really. The quiet one is low power too
I am leaning towards the Q One 4000. The head height GPH is still good. The SP2 loses a lot of GPH even at 4.5 feet.. hmmm
__________________ Ashr Red Sea Max 250, 66g Mixed Reef