Just bought £1k of bitcoin on CEX.IO and was surprised to discover a 6.5% hidden fee of £65 was added, which I was very annoyed by. I did a fair amount of research before signing up and nowhere did I read about this 6.5% hidden fee and nowhere during the purchase did CEX.IO inform me that I was about to be charged a £65 fee. I wouldn't have even discovered this had I not dug around for my transaction report. I think this is very deceptive. To avoid this you have to use the "trade" option to get the 0.25% fee's. If you use the "buy/sell" option they charge the higher hidden fee. If you avoid this hidden trick CEX.IO will probably work out fine for you, but it doesn't fill me with trust for an exchange who bill themselves as "trusted and secure".