Craigs is a drag. I use both, but Kijiji is much easier to navigate (both for sellers and buyers), has a much, much better search engine for buyers, and does not mysteriously boot one's ad off (a real issue on Craigs, where some of my ads are banned with no explanation, and no notice, despite not breaking any rules).
kiji censors too much.
Kijiji is very strict with rules. One thing wrong and you're banned for life.
Simple text interface
Easy with lots of inquiries
The photos you upload are much better quality on Craigslist than on Kijiji.
I don't want spam.
Actually you can make an account with craigslist and have control over the ads you have posted: delete or edit anytime, and even repost an old ad. I prefer the speed of loading over fun but essentially useless graphics. I also like how the ads are locale-specific.
I don't want junk e-mail
the purpose is to get to the ad and not getting unwanted ads.
good
Fast and efficient. More substance, no ads, less flash.