I've had a terrible time with Kraken. I have attempted to get through their verification process 4 times. Each time it can take a week or more to receive a response. The response is usually very difficult to interpret. There is lots of boilerplate text. I signed up sometime over the summer, it is now January and I still am not verified. I've switched to Gemini and won't be looking back.
Overall a good product, but many technical problems + the company is taking a position against the clients by disabling trading at times, suspending market order execution, or creating an artificial slippage which they then take to their own pocket.
- I used to only use Poloniex because I got used to the UI, but I've slowly moved over to only using Bittrex. While both are seeing massive increases in usage lately, Poloniex had been giving major issues going down altogether, not executing trades, or withdrawals taking forever. Both have their flaws but I would recommend Bittrex.