I use blockchain bitcoin online wallet, because this is my first bitcoin online wallet since i still new about bitcoin. Actually i also have another wallets, but i never use it anymore.
Yes, blockchain.info is the best online wallet and has very high security measures to protect your bitcoin from been stolen, I had used it for some time but hard to switch over to blockio because they found the later to be more simpler and convenient as per my personal needs.
I am using bitcoin wallet for the first time is blockchain.info too. My friend suggest to use blockchain.info because it easy to use and secure.
But actually the other bitcoin wallet is also as good as blockchain.info, that is have different good features, and it is dependent which one the bitcoin user like.