Bitstamp was one of the first Bitcoin exchanges out there, and because of it, they have very high volume / high liquidity markets. 📊 For a long time they resisted supporting “altcoins” (coins other than Bitcoin), but about a year or so ago they opened up the exchange to a handful of top coins. The trading fees are very low and affordable, and I find the user interface to be very simple and straightforward. It is a “centralized” exchange, however. So be careful about how many coins you leave on it (ideally none). They have been hacked once before, so there’s no reason to believe it couldn’t happen again. Source: https://www.coindesk.com/unconfirmed-report-5-million-bitstamp-bitcoin-exchange/
One of the oldest exchanges still around and that is for a good reason. They have had some security issues over time, but it seems they have fixed that and become much more focused on security. They are a legit exchange with proper banking relationships. They added Segwit support far before other exchanges and even pay the withdrawal transaction fees for any coin on their trading platform. While some may complain that they don't have very many cryptocurrency options, I believe they have done well focusing on a core group. I didn't use bitstamp for a long time, but recently came back and have been pleasantly surprised.