Eheim over Fluval for most

Had a bad run with the Ecco range, but those that haven't ran a Ecco will usually go Eheim everytime...
Sice you asked for other options, if you are on a budget (or want an equaly good filter to a Eheim without paying through the nose IMO), Tetratec seem good, and in a few years, once proven, they may start to shape up against Eheim, but untill they have been available for over 15years, they won't be able to mount a challenge, as that is where most people get to with their Eheim's before up-grading or leaving the hobby

TT are running strong on everyones tank, where people bothered to read the manuals and maintain them right.
I have had electric shocks from Fluvals before, and one of my mates had a Fluval dump half their tank onto the floor in a few minuites, during a family meal...

Needless to say, I won't be buying another of those
Fluval are usualy associated with high maintanance, difficult maintanance, leaks, noisy running and electrical issues.
Eheim and TT are usualy associated with easy of use, longevity (Eheim at least , TT's haven't been about long enough to qualfy for this, having only been on the market for arround 4 years), low maintanance (Mine gat cleaned one of two every 3 months on a heavily stocked discus tanks recieving 4 heavy feeds a day), Literally silent running and only leaking if you allow the seal rings to dry-up by not applying Vasaline. Even in this case, you can run the seal dry for arround 3 years without encountering a problem...
HTH
Rabbut