Which exchanges would you suggest for security? Which ones to avoid? How to tell a good one from a bad one?
Coinbase would be the safest exchange since it's backed by the US government so they are bound by certain rules and restrictions. You can buy cryptocurrencies with fiat on Coinbase which is handy. But i don't like it for professional trading.
Personally i use Binance since they have the biggest offer of cryptocurrencies, a lot of liquidity and volume, low trading fees, ...
I trust Binance enough to give them my funds, they have some good security features.
Always use 2fa on exchanges! So when hackers have your password they still need to bypass a second layer of security.
Make sure you have a very strong password and don't use it on other services or website's, it have to be an unique password. This lowers the change that your password can be obtained in a database breach.
Check out my review about Binance here:
https://steemit.com/cryptocurrency/@niel96/fkextygqq