Kraken and Poloniex are GARBAGE exchanges. Kraken had problems in the past with payouts and also screwed people over when marginal trading went down the gutter a few years back. Polo's support is HORRIBLE. But 90% of exchanges suck.
You have very bad experience i think about exchanger because you said that 90% suck.
However although we can not believe any exchange but we still need to use 1 of them to trade.