Personally I prefer Ebo Jager as they are consitantly reliable. I have used both visitherm and ebo but the ebo seems more consistent in the temperature control and to last longer. My visitherm died while the ebo's that are more than a year older than the visitherm was are still going strong.
I have two 250 watt Ebo's in my 75. My temp only fluctuates a few tenths of a degree. Thats Pretty good considering my den gets down below 60 degrees at night.
I have an Ebo in my 55 FW that I've had around for the last 6 years or so and its still as accurate as when I bought it.
I won't buy anything else...
ebo jaeger, i have used them for 15 yrs and i have not had a problem. in fact i still use the first one i got 15 yrs ago. the glass is thicker than the visitherm and they hold the temp better too.