I am using this PRO version of Coinbase as it is a easy to use exchange with competitive fees (it is suitable even for beginners). It is one of the exchanges highly regulated in USA and first one which announced its IPO recently with the valuation up to 100 bil. USD. This makes this exchange as a good choice. They have enough security (never hacked) and good name in the industry. I remember that they had even a free withdrawals of crypto (before high GAS fees). There is high user base and enough liquidity to perform trading but as I am more oriented for alternative altcoins in my humble opinion there are not so many trading pairs. On the other hand I usually buy newly listed coins on Coinbase PRO as they have tendency to raise soon in value after listing. The main issue with the exchange is sometimes technical issues when there is a huge hype in trading. This could lead to the bad experience. Overall it is a good choice alongside Coinbase app where to trade even for new comers.