I have been using this exchange to sell and buy cryptocurrencies for several years because it offers good security and also has a large volume of market for the most important cryptocurrencies such as Bitcoin or Ethereum.
What I like most about this exchange is its bet for the security of the account, since it is evident that one of the most important problems in the world of cryptocurrencies are hacking to exchanges. For this Bitfinex offers several security measures for your account.
They also have their own currency called USDT that offers parity with the USD dollar therefore it is possible to keep your funds in dollars at the same time you have a cryptocurrency called USDT, this token can be easily transferred as if it were Bitcoin.
I recommend using Bitfinex as a platform to invest in Bitcoin or ETH mainly since the volume that moves and the liquidity is among the highest in the world, in addition the Bitfinex platform is very safe and is something to take into account when working with virtual coins.