Planted Tank Guru
Join Date: Jan 2010
Location: Contra Costa CA
It has long been known that you get what you pay for. Especially with aquarium heaters. The cheaper brands are just that: Cheap junk.
Get a name with a reputation, not linked to any store:
Jaeger or Ebo-Jaeger has been good, and I think they still are.
Tronic is a good name.
I have had several Penn-plax that were good, though I do not see many reviews of that brand.
There are others, look around several aquarium sites and see what they say in forums that might be called 'equipment' or 'product reviews' or similar.