FLUVAL U2 filter

[cgt_2010]

HI to All,

I will be in the US this August for vacation, Im planning to replace my current Over head filter in my 20Gal aquarium(so, far I have to cons with this). Has anyone out there using this kind of brand.(Aquaclear/Fluval) Actually, I wanted to buy Aquaclear 20 (side-hang??) filter but I don't think it will be possible since my aquarium has a rim. For me the best option will be FLUVAL (under water filter) Are any of this two good when its comes to performance? What are the advantages and disadvantages? Thanx for the info!