I have heard good things about the Visitherm Stealths, but have not used any personally. I run Won Bros Pro-Heat titanium heaters and Ebo Jagers almost exclusively...one nice thing about the Pro-Heats is that they are available from 50W-500W.
G. A. Christian Bilou, Herpetologist
Founder/Director, Reptile Rescue Alberta
Past-President, Calgary Aquarium Society