Changelly is a trustable site and safe to use to exchange between various cryptocurrencies. Personally, I love the account history feature because the exchange doesn’t often happen in real time. You can check out their official thread here:
https://bitcointalk.org/index.php?topic=1435275.0Also, check out a new competitor Nexchange.io that doesn't require accounts, passwords, or your email address.
Official announcement thread:
https://bitcointalk.org/index.php?topic=2138691.0Throughout September they are offering 0% fee trading as promotion, basically their price is the same as Kraken or Poloniex. I've used Nexchange.io several times and it's been really fast and reliable... very nice service for quick exchanges.