I believe they're called Eheim Jager now =) I have three and they are all very consistent with their heat. The only thing is, the dial isn't entirely accurate, but sort of jiggle it around and compare to your lab grade thermometer to set it perfectly. It varies by 2 degrees from where you think you've set it, but set it correctly and it's perfect.
I find it's easiest to turn it all the way cold until you hit the right degree you want to set it at. If you go the other way around, it doesn't kick in very well. Also remember, the thermometer it has built in is slow, so moving it slowly before it turns off / on to set it makes sense.
Get the eheim jager!