I always swore by Jager, and they worked great for me, but the last 2 that I got have been pretty iffy. They work, but the temp and dial are way off what they should be.
I use on both my tanks Eheim Jaeger's and I dislike the way that you have to set the tempeture, but I just hook them into an Inkbird controller and they work perfectly. I have the temp probe inside the tank and a digital thermostat to make sure the temp is correct. It seems like every heater on the market has complaints.