Yes, i think that MyEtherWallet have enough security to use it for Ethereum and erc20 tokens transfers. But you should always check the green lock at your browser.
I have been using my ether wallet, and until now it's very safe, but if you're still in doubt, there's another alternative, MetaMask, many of which say metamask is safer than myetherwallet, metamask works like add ons in your browser.