you are full control of the private key and myetherwallet can be used for buy the ICOs projects, also you can used jaxx.io to store ethereum but jaxx doesn't support for purchase the ICOs at least for now.
There are open scam accusations against the wallet for stealing coins in the past and it's not recommended to use the wallet.They say the private keys are generated at the client side but who knows what it really is until the code is open-sourced.