recommend eheim, don't care where their heaters are actually make, it is the design and quality control that matters, hence the brand.
Not my experience.... Out of 2 one failed in shortly less than a year.
Temp adj ring froze.
A warranty replacement direct from Eheim is UN-calibrateable.
Not enough notches.
Adj. wheels are WAY too stiff on mine for easy adjustment.
Personal note: They seem to be cruising on their past reputation.
My other go to brand heater isn't all that impressive either.
Out of 3 Fluval E series heaters one became un-adjustable..
The others have been rock solid for a few years though.
Geeky enough for me though and do like the plastic case.
The low flow warning can be annoying though and the fact it can't really heat up a tank from cold.
Think that's because it's solid state and pulses the coil which of course has the advantage of lower hysteresis.
Just speculating on that but even instructions state you need to be near set point for the heater to be effective.
Blue/Green/red led temp panel is of course a personal choice.
Currently on one tank I'm using an second hand Marineland Precision that has behaved flawlessly.
Has to be over 10 years old by now.
Can heat an aquarium from ice cold to set w/ no problems.
Could probably boil a cup of ice water in a few minutes..
The old bi-metal snap switches may be functional they certainty aren't very advanced..
I really don't recommend nor condemn any name brand ones "except" for the exploding Cobalt Neotherm ones..
Too much bad chatter and the meltdown failures w/ goo is a really bad way to fail.
Prob. good enough..
Marineland had a recall on a part. model so one needs to be careful w/ used pick ups.
Good thing is they may still offer cash in exchange.
Fun story, picked up a bunch of used aquarium stuff including a 55gal tank.
Had 2 of the below heaters.
Contacted marineland and got a good chunk of cash back I paid for the stuff.
Well bought it all pretty cheap to start with.
At least 5 years after the recall. I was impressed.