I don't think Blockchain.info give you the ability to export the private keys anymore so you will have to import the 12 words seed to MetaMask for example and then add the contract address of that token so you can spend and see it.
I don't see any seed to import in metamask. The choices are private key or JSON file, I think you can only import is ethereum private key in metamask. And I heard many good reviews about this wallet and test them for a long time and until now I am still using this wallet.
If you wanted to use this for saving your token you need to add them first in token tab then you need to put the contract address, decimals of precision and token symbol before you can add your token into your metamask wallet.
And i think MEW would be the best choice if you wanted to see all supported tokens and for safety purposes but you should know how to send token or ethereum because its asking for gas or gwei you must set it properly because if you didn't set it properly your fee is not refunded if your transaction is not successful.
