Always choosing the centralised one because they are very much reliable and can give us big protection against the hacks and frauds. The decentralised exchangers are just too public and anyone can any coins over there to scam us and we will never know our money got stolen in the form of crypto coins. Mostly they are scamming new ICO's also which are not tolerating this as the ICO money gets carried away due to pump and dump activities that are live on the decentralised exchanger. Centralised one also has more coin volume and thus better for the trades.