Won Pro 350 in 90 gallons of mixed connected tanks. Temperature varies 1 degree in 24 hours. I have heard bad things about it , but I am liking it.
For my 10-20 gallon larvae tanks I am using Stealth Visi Therm heaters. I love them. No light to attract and then kill the larvae. Nice steady temp.
Also heard bad things , but again, I love them.