Best one I ever had was a Visi-therm submersible back in the day when submersibles were brand new. It lasted me 10 years and ran like a Swiss watch. I broke it after I forgot to unplug it during a 50% PWC
. Silly me.
Replaced it with a Hydor THEO. Less than a year later and it's on the way out. The thermostat is going. I've got it set at 71 (lowest setting) and it's currently holding the water at 78. It's been steadily getting warmer over the past couple months.
I've also got a Hydor ETH in-line. So far, So good and very stable temps.
Finally, Im running a Hydor HyroKablewith a ThermoSET controller. All is well there, too.
The ETH and HydroKable is only a few months old, so we'll see.