I am going to say helix or herpstat only...... I know people that use both and both are very reliable. Herpstat is a bit cheaper.... The bad thing with a on off is the fact that the contacts will eventually fail, and when they fail they usually stick together not allowing the thermostat to turn its self off so if you go that route especially with a bator use a double ranco or something simmilar so if one goes out the other will keep it working properly.