I use Coin Wallet from the UK and it all works brilliantly for me. Easy and intuitive app for IOS and simple website. No bugs found on either since I joined on 6th December. I like that you can check exchange rate, exactly know what amount of currency you will get and just in a few clicks you exchange one currency to another. It took 10 minutes to register and I've bought and sold bitcoin, litecoin and Ethereum using the app.See full review