You are wrong!
Blockchain.info - you have access to private key.
Coinbase normal wallet/vault - you don't have access to private key, plus 48 hours delay for each transaction.
Coinbase multisig vault - you have access to your private key, plus 48 hours delay. You can also create and sign a transaction using tools such as coinb.in, but it is insecure, unsafe and complicated or hard for users without much knowledge on using them.
You can set custom fee in Blockchain.info and AFAIK, you can't set custom fee in Coinbase. Correct me if I am wrong!
When I compare all pros and cons, Blockchain.info is better. Vault is also not much better. If you are just looking for a multisig wallet, there are better services/software out there. There are, however, advantage in using Coinbase if you are a frequent trader or if you send off-chain transactions.
Edit: I don't understand how you got "low" transaction fee in Coinbase.
But if you send high amount of bitcoin the network fee are asking the same fee as small transaction.
It is not a good choice if you using coinbase for small transaction but if you are using coinbase for large transaction the network fee is reasonable..
If you want to have fully control with the fee use other wallet instead like multibit HD or electrum they have option to use dynamic fees or either manually input you fee but like other said always check the https://bitcoinfees.21.co/ for transaction speed estimation and what the fee can give you satisfaction..