Yea blockchain.info is definitely a solid wallet, i think its safe to use it up to 10 bitcoin.
After that you need offline vault.
No, it's not. Blockchain.info is not a secure online wallet. Now, the only secure wallet which I can think of is GreenAddress. Blockchain.info seriously flawed. It may have been a secure online wallet earlier but not now.
are my wallet is secure ?
i use blockchain, i back up it and i restore to electrum wallet ( android) ?