I started with Kraken but really didn't have a good experience with the UI so I moved over to Binance and have been loving it. I use Coinbase to move funds from my bank account to one of the coins available on Coinbase, usually ETH, then send the ETH to. Binance get XRP and store offline in a Ledger Nano S
Binance also has a really great mobile app for Android and you can cut your fees with them by 50% if you leave some funds in their Token. Also trades are near instantaneous which is pretty cool and they have a great selection of Alt Coins a bunch of which have done great by me so far.
I've sent tokens back from Binance to Coinbase and then turned them into USD. I've also sent from Binance to other locations including hardware wallets to keep it 'offline'. All seemed good to me. I also thought that the iOS app wasn't available through the app store, only via a third party. Just an FYI for those thinking of Binance on iOS