It's probably hard for anybody to give a sweeping answer because different people use their system in different ways and have different priorities and expectations. I can supply one narrow opinion. For a small system (16 cameras max), 4MP, no PTZ, recording 24x7 with event triggers, and maximum of about $200 per camera, I've used both Dahua and Hickvision-based systems. My conclusion is that Dahua is far ahead in what I care about: Image quality, ease of use, and inconvenience/impact of bugs. They're both full of bugs and have lame user documentation, Dahua being less lame in that regard.