I've been using this exchange for a couple of years, but I can not take it anymore.

The reasons? There is are lot:

1. Support. It is almost doesn't exist. I have unanswered ticket that I sent months ago.

2. Website bugs. For example TRADE HISTORY for market trades show empty. Console indicate are lot of this errors:
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Uncaught TypeError: Cannot read property 'oScroll' of null
    at showMarketLines (plx_marketTables.js:505)
    at resetMatketTableHeights (plx_marketTables.js:152)
    at plx_exchage.js:251
2public.poloniex.com/?command=returnTradeHistory¤cyPair=BTC_ETH Failed to load resource: the server responded with a status of 403 (Forbidden)
exchange#btc_eth:1 XMLHttpRequest cannot load https://public.poloniex.com/?command=returnTradeHistory¤cyPair=BTC_ETH. No 'Access-Control-Allow-Origin' header is present on the requested resource. Origin 'https://poloniex.com' is therefore not allowed access. The response had HTTP status code 403.
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3. API issues. In case of use public API like
https://poloniex.com/public?command=returnTicker
polo indicate something like this
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ONE MORE STEP
Please complete the security check to proceed.
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CAPTCHA for public API ? seriously?

There is no desire to trust money to a service of such poor quality.