It is rather difficult question to answer since both the Poloniex and Bitfinex have their own flaws and advantages. Nevertheless, important thing is what is better for a person in question, since it depends on personal characteristics.
It is a legitimate crypto exchange since there is no fiat currency in flow on this exchange. Founded in 2014, today Poloniex has over 40m dollars of value in Bitcoin daily. To begin trading via Poloniex you have to trade some Bitcoin first. For Bitcoin, Poloniex represents a home since that is the exchange with largest volume of Bitcoin traded. If you are considering altcoins as well, Poloniex is a place for you since it has the biggest variety of alternative cryptocurrencies – over 60 different altcoins! Considering privacy issues, Poloniex doesn’t deal with traditional currencies, so there is no personal information needed in the first place to register. It is a great advantage if your major concern is to keep your privacy.
It is a great place for the beginners since with Bitfinex your trading is really easy and simple. That is one of the greatest advantages of Bitfinex comparing to the exchanges globally. Its design is very practical and intuitive. Based in Hong Kong, Bitfinex was founded back in 2012. That is a big amount of time on the market in today’s crypto community. Daily, Bitfinex has the greatest volume of Bitcoin traded at this moment. Downside is that Bitfinex offers only 7 cryptocurrencies available for trade. Still, those in flow are Monero, Zcash and Ethereum – for some traders there is no other choice in the first place. Still, remember to keep your assets on your wallet where it is safe, unlike leaving it on the exchange.
These are some key facts concerning these two exchanges. If you are primary focused on Bitcoin and Ether without altcoin trading, the right choice would be Bitfinex, since it is simple to use and it offers possibility of quicker trade. Nevertheless, do not lose Poloniex from your mind if the privacy is key factor when it comes to your own choice!