I am using a single wallet at this time,which is block.io because i like its simplicity.No need for me to use more that one wallets because my bitcoin earning are really low and i am not even able to fill my single wallet with much bitcoins,may be when i earn more then i will use another bitcoin wallet.
Block.io can only be good for small level merchants and i don't like to use them as web wallets for daily life. You can take a look at blockchain.info , coinbase.com , xapo and electrum wallets which are meant to be online wallet and block.io is better for merchants to accept payment from customers.