It works fine 99.9% of the time. I know many people who have used Coinbase / GDAX for years without any issues. You can also try Kraken (they just upgraded but

It works fine 99.9% of the time. I know many people who have used Coinbase / GDAX for years without any issues. You can also try Kraken (they just upgraded but had a lot of site reliability issues before) or Robinhood once it launches next month.