LocalBitcoins - Fakten & Informationen
There can be complications which mostly come in the form of couterparty risk - where someone refuses to go ahead with the trade as the price in the market has moved in their favour - so they gain by keeping the bitcoins or USD if they have gone up. Localbitcoins has a dispute resolution system in place to handle these sorts of issues - but on the flipside there is a reputation based system - so you can gauge whether your trading party is reliable or not.
Trading fees vary and depend on whether you have placed an advert to sell - whereby LocalBitcoins takes a 1% fee.
In all a good means to exchange Bitcoin but it doesn't have the razor edge price discovery, and execution time of more traditional order driven exchanges.