Most here will say the 5442 series is the gold standard.
They come on ideal MP/sensor ratios and have fixed lens to varifocal up to 32mm.
Many here say 4MP is all that is needed for surveillance.
Dahua feels confident in this series in that they have new cameras out with better specs that they could have gave them different model numbers, but instead chose to keep them in the 5542 family.
Many will say the equivalent Hikvision 4MP on the same 1/1.8" sensor is just as good, but at that point, that is the debate of Ford versus Chevy or Toyota versus Honda. Personally I wouldn't trade out the 5442 for the comparable Hikvision.
Many will say Axis is the top of the line (at least in the prosumer type line), but they are also 5 times the price. Most of us don't see an appreciable improvement in picture quality for 5 times the price.