I think you are better off asking for peoples adivce who own both the eheim and fx5 so that they can compare them first hand. I have an fx5 and love it, its so quiet that I sleep beside it everynight. I also hve an eheim, I am not sure of the model number (it was given to me with a tank I just bought used), it was missing parts so he gave it to me for free. I am having a really hard time figuring out what parts are missing and what I need. I know the impellar is out, and I have found that I have to buy three or four peices just to assemble the impellar (not sold as a group). For this reason I have not yet been able to set it up. I will say that the clips on the eheim seem to be made of crappy scrap metal, where the fx5 is built like a tank. I also own an xp3 and hate it, its currently running on my 40 gallon because I dont think it can filter anything bigger sufficiently.