I used to use Won Bros. titanium but I had few die on me recently. I've replaced them with stealth heaters and so far, so good. The only complaint I have, is there is no way to know when the thing in "on" because there is no light.
i bought a couple of them before and they died on my right away..... i use stealths on all most of my tanks and a couple eheim jagers im very pleased with both......