Since I joined this forum and started getting ERC20 altcoins, I only use MyEtherWallet because for me it's simple, safe and secure as long as I am responsible enough for keeping my private keys and don't let outsiders get a copy of my keys, I'm always good.
Freewallet.org is for me a complicated because you can't have a copy of your secret or private key.
There is only one ERC20 wallet that for me is better than any third-party wallets, that is Eidoo Wallet.
But, hackers could be able to steal your keys if you are not careful enough, that's why experts are recommending hardware wallets like Ledger Nano S and Trezor or any hardware wallets available in order to protect your keys from hackers and hijackers.