Personally I like the visi-therm and the visi-therm stealth. They are the only heaters I have used that have not broke. My oldest one is about a year old now. I recommend the stealth over the regular unless you need a 300Wer.
i'm using 2 100w jagers in both our tanks, & haven't been disappointed yet.
i must confess that the main reason behind me buying them was that they were the most expensive heaters in my lfs and i assumed they were the best quality they had
I use a Tetra Acura 300w heater, It's not the cheapest around but it has been running correctly all the time. I guess heater quality is somewhat over looked in this hobby.