I've been a buyer and seller on CL in a few different cities. The only "red flags" I've dealt with were undisclosed flaws on items. That and a guy that wanted me to "deliver" a piece of equipment to a not so hot part of town. Oh, and a scammer that wanted to write me a money order and have me mail an item. The majority of the people I've dealt with have been fine, but I'm not a very frequent buyer or seller. Biggest things on CL IME are undisclosed flaws from sellers and buyers that want to low ball. How fast your item moves may depend on your local market. With several items in one place I lived in, it was easier to just put them on eBay where they would sell in one week or less.