Tetratec are the only brand I have bought two extrunal filters from. I have also ran Fluval, Rena and Eheim.... Guess where my vote goes
Fluval have a reputation for leaking, they channel IME and clogg in two weeks on any kind of reasonable stcking load, when most other brands will run for months without attention... Very poor IMO.
Rena are great filters, though the XP4 has issues currently as far as I'm aware with the impellers torque being too much for the impeller shaft. The main Seals are IME unreliable, needing replacement on the second opening after the last change of seal. Standord media will need to be changed with Rena, as there is a lack of Bio-media and lots of expemcive to replace ammonia-sucking chemical meida that you would become dependant of if you left it in
I had a bad run with Ehiem, with both the origional and replacement filters breaking within a few weeks of being set-up. Customer service with them was very slow to do anything about it... On the whole though, Eheim have the best reputation.
Avoid any filter that has a build it heater, as these have more bugs than a maggot factory

Also, avoid Eheims Ecco range, as these also have issues. Pro2's are probibly the best if you go down that route.
I'd personally go Tetratec EX1200 again
HTH
Rabbut