I have two 200w and love these heaters! This heater includes an Electronic monitoring system, thermal sensor, and LCD temperature display. The LCD screen is color coded from the temperature you set it. Green means safe, Red means high Temp, Blue Means low Temp. Another positive is the heater is guarded by a plastic cage so fish can not come into direct contact with the glass (Heater core). The mounting bracket is really nice but is a real pain to remove. I have owned a few different brands and models but this one looks nicer and is really easy to read and operate.

Have an E-300 in my 36 gal bow front ... installed it just to the side of the water return of my HOB filter ... unless the filter was set for highest speed got "Low Flow" reports from the heater AND the digital read out frequently reported temps that fluctuated between 71 and 84 (temp set at 78 ... the in tank thermometer reported 70 to 72) ...

Both instances with the heater could/probably be attributed to the fact that I had the filter installed perpendicular to the bottom of the tank - when I angled the heater to about a 60 degree angle ... voila! heater reports constant temp of 77 to 78 and no "low flow" readings, in tank thermometer (on the other side of the tank, displays temp of 74 to 76) ...

Interesting how the heated water rising straight up to the heater's sensors threw a monkey wrench into the heater's works ... now I understand why almost all heaters I see in pictures of tanks have the heater on an angle ...

Back to the E Series heater - looks to be good, reliable and consistent after 3 months (and if you install it on an angle)

Thats a problem I have run into with it up and down. Most of my tanks are running 10x over volume.

I actually have one laying flat with just a spong filter in it. I don't get the low flow message at all now.