Define better? 8MP musst not be better, its based what you gonna do with a camera, and whats there goal. If you wanna look only a door entrance with 5m distance, 2mp is enough. If you wanna look a parking lot or a company ground, 8mp are good for details. If you wanna do a alarm system with cameras, EasyIP 4.0 or Deep In Mind is the key.
So there are many details to think about it. Distance - Range, IR Range, Height, fov, Detection Functions, Optical Zoom for more Details and so on.