While there is nothing wrong with blockchain.info (I use it myself for small amounts), you do NOT have total control of your coins.
Websites can get hacked, and their owners can steal, there have been numerous examples already.
I thought Blockchain.info's owners had not acces to accounts because information is encrypted on the browser before reach the server.
Well what they say is ...
we are protected from hacks as all of your private keys are encrypted with your password before leaving your computer. We do not hold a copy of your password, and thus are unable to view or spend your Bitcoins. You retain full control of your private keys, so your wallets can never be seized or blocked and can be imported into any desktop Bitcoin client.
Now I have no doubt that this is true, as I said I use it too, but never underestimate the ability of bad people to find ways around anything.
Too many times sites have claimed to be ultra secure, no chance of anything being taken, all funds stored in cold wallets etc etc and either through hackers or malicious admins people's bitcoins have gone.
It's just my opinion that the more secure the private key (ie by only me actually having it and no-one else, or being offline) then the more bitcoins I trust there.
Also worth mentioning that the last bit 'and can be imported into any desktop Bitcoin client' is only true if you have the private key, if the website vanishes and you haven't previously got it, what then ?