Myethywallet is a non custodian wallet which means you are responsible for the security of your asset in a large way. You can either connect to myethywallet using browser or mobile application. You have the privilege of connecting your ethereum wallet that you have before to it or create new one.
When creating a new account on myethywallet, you will be giving a 24 seed phrase or mnemonic words which they will tell you to keep seriously, because should you lose it, there is no way that they can get it back for you, because the team doesn't keep neither your pin not your password.
There is an opportunity to create more than one account which you can give different names for management purposes. There is also a swapping function where you can swap some erc20 tokens for ethereum or vise versa, this save the user from hassle of transferring to an exchange. There is an opportunity to even buy ethereum with credit or debit card using myethywallet.
Another interesting thing about this wallet is that, they make a cryptocurrency tutorial especially ethereum, so that new users will at least have the knowledge of what he/she is going into.
But when it comes to transactions fees within the wallet, though one may say that is not too much but if you now compare what they use to take with another wallet doing same service one will see that it is too much, so new users should take note. But using it will help one to avoid some delay.