MyEtherWallet is safe if you do not reveal your wallet key. I use a wallet MEW so far has not had any problems so you can trust that your property is safe. And I advise you to be careful with impost websites, if you enter the Key code into those sites you will lose your property. Impersonation sites are often different in the few letters of the web address you should look into.
Yes it safe, as long as you know how to protect yourself to the hackers, activating every possible security and bookmarking the website itself, the best way to secure it is to make sure that you completely save and secure your private key, never ever to share it and make it exposed in any event while working online, with saving private key you can be assured that your assets are fully safe inside this wallet.