Both are beautiful. Females are every bit as colourful as males - their colours are just different from males.
Males tend to cost more (with panthers anyways). Males may live longer.
Males are larger than females. Some would say females dont need quite the same size of cage as a male, and that they can be kept in a slightly smaller cage. I personally dont agree, as I believe my females actually make better use of their space (more active) than my males.
Egg laying isnt a big deal, but it is one thing you have to accomodate with females that you dont with males. Unless of course you keep your female in such a way as to prevent egg laying.
Females are less likely to go on a "hunger strike" - they tend to be less picky. A new or less knowledgable owner may be more inclined to over feed a female.
Females need less heat than males (if not breeding).
I usually suggest a male to a new owner. I usually suggest a female to someone who already has chameleon experience.