Coinbase.com pays for all transaction fees, which means that your transaction aren't in danger of being in stuck in limbo for not paying a proper fee. That however, doesn't mean that it offers all the flexibilities a normal bitcoin wallet would offer, it doesn't even give users access to private keys.
Do they pay fees when sending from their multisig wallet or vault? I think both offers partial private key access.
For moving money out form the vault you need to (vitrualy) release the money into your coinbase hotwallet. A transaction which takes 2 days to clear for further 'protection'. No fees though.
It's good for a personal wallet but nothing more. Your account could also get shut down for illegal activity according to US law, the way they detect this isn't open. They probably monitoring some addresses from gambling websites.
