I have been using Bitfinex API for about 10 months now. I am really impressed with the amount of flexibility it offers. It can show up to 5 decimal values. The prices are up to date, they have been updating the API for quite a while and adding many features which are on the main site. I love the number of features and liquidity the exchange provides. I mainly use the Margin trading and margin funding options which enables me to perform professional trading techniques. I wish they would allow US citizens to register and trade. The support has been excellent to me.