I trusted more in binance exchange because seems to me very hard security and surely will not get hack, and it is good to trade because of high volume.
In fact, only services without registration will be able to guarantee the safety of funds, since you do not give them access to all funds, but give only a part for the exchange.
I think that Changenow, in this case, will be the best option for the service without registration. I use them now and find this service very convenient.
I think this is really one of the exchangers that I can trust.