What I have heard is not terribly good, but is anectdotal so may or may not be worth anything.
I'm old school and the only filter I have run across that I am equally satisfied with is the Rena Filstar line, but they are relatively new in comparison and I'm not sure they will have the longevity that you can expect from Eheim. For my money, Eheim is the way to go if you can scrape together the funds, because when I look back at what I have spent on equipment that winds up needing to be replaced, I would have saved $$ if I had invested in Eheim to begin with.