I needed a heater for a new 33 gallon long tank, looked around, $60 for a good 150 Watt heater at the LFS, I said no way, I can do better. I checked and found this, I got it for $12 (I had it for several months, I think the price went up a little since I bought it) and I have had zero problems with this. I have it in the tank, slightly angled (Even though the instructions say to keep it straight up and down) and she keeps the tank right at 80F. It is quite long, like 15 inches or something. I have had no ill affects having it angled though, no water inside of it or anything. The only thing I can even think of complaining about is that the number on it don't necessarily match my thermometer. I mean my thermometer consistently reads 80F with 1 degree fluctuation, but I leave this heater set to 76F. I had an Ich out break once, I had it set to 80F, kept the water and a consistent 87F, Ich died, fish all survived and never had the Ich return. It kept it at 87F for 4 weeks straight with tiny fluctuations, spot on. I mean, that is no big deal if the numbers are a bit off, I think most of these heaters are like that and it probably depends on size of tank, 33 gallons is pretty small for this bad boy. Just find out what temp on the heater corresponds to what actual temperature you want, set it, make minor adjustments, once she is set, forget about it. I know some people complain it turns off before it should and this and that. All heaters will do this, they heat the water around there base where the heat element is, warm water rises and the thermostat is at the top of these units and it will turn off. Once the warm water distributes itself a bit it will turn on again. It gets your tank to the right temperature, but it has to turn off and on and get your tank to average the temperature you want and its pretty accurate, a few degrees +/- at most. Its like an oven, no oven you set to 350F ever stays at exactly 350, they constantly fluctuate about 20 degrees above and below the temp you set them too, but it averages 350F. Think of that next time you are making a cake! If this really concerns you, buy a powerhead and aim it at the heater or, buy a small heater, a size or 2 smaller then your tank size (A cheap one) and run it on full all the time with a second heater with a thermostat. The one on full will let the temperature drop so slowly, the second one with a thermostat will come on as soon as the temp drops less then a degree and stop as soon as its back up to temperature. I do this on some tanks, I use this method on a 30 gallon breeding tank and it stays constant at 77F, it never flinches. No product is perfect, this one works very well with the tiniest of flaws, probably isn't much better on the market out there, and definitely not at this price point. I see the bad reviews for these and many seem like they could be a bit ignorant. I see reviews saying they have black ghost knife or loads of cichlids, large fish they claim to have for years (So they should be fully grown). Either your tank is overstocked or you need more then one of these. One reviewer says that it would keep his prized $600 Discus tank at 80F while set to 90F in a 70F room and he needed it at 90F. Asking a single 300 watt heater to heat a tank 20F that is big enough to house $600 worth of fully gorwn discus is impossible, 3 or more of these would be needed. 300 Watts is good for about a 50 gallon tank, it will heat it up to above 25F above whatever the room is at, above 50 gallons, it won't be able to heat the tank as much above the room temperature, and this decreases fast. 65 gallon and up, thinking about a second heater. And so many people complaining about it malfunctioning. It says in the instructions to plug it into a Ground Fault Circuit Interrupter plug, not a standard household plug or a power bar, a GFCI outlet and I bet most people didn't do that. There just seems something off about many of the 1 star reviews, errors made by the user and not defective products.