Hi there,
I had these filters;
-Aquael utramax 2000 (5 blades rotor axle broke after 2 months, got a new 6 blade rotor after 5 weeks, works fine since 5 month now...let's see how it hoes in the future)
-Eheim pro 4+ 600, loved the silence and flow , disliked the cheap plastics and low filter media capacity
-Oase biomaster thermo 600, superb quality, average flow, horrible humming noise, had to get rid of it, it's just too noisy in my living room
-Actually running the Aquael Ultra 1200, good flow, good capacity, quite silent...cheap price, seems more reliable than the ulltramax series (no prefilter)
Well the ideal filter to me would be the price and the capacity of the Aquael, with the noise and the customer service from Eheim and the prefilter /plastic/ thermo option from the Oase....hard choice.