Smelly/cloudy water would be perfectly fine if it was clean enough to drink - even if clear water would be perferable. I'd definently pay more for a unit that made clearer/cleaner water.

Asthetics wouldnt matter much to me as long as it worked, but making it look slick cant hurt.

Portability would be nice for personal use. Something small enough and light enough to carry around yourself and move around to where ever needed.

As far as durability goes, something I could save for multiple disasters or years without disasters would be perferable.