Online blockchain, because it is very easy to use and can allow many type of protection. I don't think that the owner of blockchain will escape with our money 
And what's about hackers? The perfect/unhackable system doesn't exists. It will never exist.
Online Wallets should only be used to save not more than just pocket money.
so what is your suggestion ?
i'm using blockchain but i've heard that blockchain been attacked by hacker recently
So make me frightened
Use a paper wallet, hardware wallet or offline wallet to keep your bitcoin safely against hackers.
You should only keep a small amount in your hot wallet.