I would say its hit or miss. if youre going to meet someone, i would go with somebody. i have had some very friendly encounters even though a few of them had items that didnt look anything like the picture they posted. other than that i have never had any problems. i personally prefer ebay, but if you cant get what youre looking for craigslist isnt a bad option.
I would say about 50/50. While there are a lot of spams on Craigslist. There are a lot of people, looking to do things the right way. The key to this is watching to see if the deal is to good to be true. Looking for clues that would suggest that the seller is actually a good seller, or someone trying to get your money.
Include the image of the real object to get a quick response. For some reason, people who put up ads with images get better responses. If you are selling your furniture, make sure you put up the picture of YOUR furniture,i.e, sofa, dining table etc. and not an image from the net.