CEX.IO IS NOT A SCAM. It's one of the largest most trusted cryptocurrency exchanges with over 1 million users and a ton of trading volume. I personally have an account there and I use it all the time. It's a great place to sell your alt coins back to fiat. The prices are generally a little bit higher there than some of the other exchanges. This makes it a great place for arbitrage. One of it's coolest features is that not only can you purchase cryptocurrency there with your credit card, they also allow you to withdrawal usd, eur, gbp, & rub to your visa or mastercard. If you plan on trading you should definitely sign up an account there.