I have had 3 DCS-2121 for almost 3 years without problems.
4 months ago I bought a DCS-2230. It was fine, but after a I changed the configuration the picture became blurry. I re-sat everything, without success. I spent many hours trying all configurations. The AntiFlicker made it clear, but the picture becomes totally overexposed in daylight. And I use it for an outdoor scenery 24hours a day, and if I turn down the contrast and brightness, the picture will be black in low light.
Suddenly, I actually do not know why/how (I think it was when changing the configuration of profile 1 and 2), it was OK. (If you are interested, you may see it live here www.bisp.no in Norway, timezone +1 GMT)
Last week I bougth a DCS-2332L, the picture was even more blurry than when I had the problems above. As above, AntiFlicker makes it clear, but overexposed in sunlight. And even if I have tried to copy the configuration that works with DCS-2230, it does not help. So if nobody have a suggestion, I have to return the camera.
PS: I have had 3 DCS-2121 for almost 3 years. They are placed outside in boxes made of wood for bird's nests (I do not find an English word in my dictionary or google translator) with a windowglass in front of the opening (so no birds inside). The boxes are sealed, no ventilation. The outside temperature may be between -25 to + 25 degrees Celsius, inside when sunlights hits the boxes it must be very warm. In the winter season the sunlight hits directly in the lens.
But: I have had no problems ever. The cameras never stops, during the cold, the heat. And the direct sunlight has not ruined the sensor. I am extremely impressed!