I felt I needed to add my .02btc to this topic, and relate my experience with Coinbase.

On Dec. 10th I placed an order with them for .30btc, after following all their procedures to the letter and linking my bank account.  The order became "pending" on Dec. 12th, and on Dec. 16th the order was cancelled.  The reason given was that the transaction was cancelled because it was "high risk", meaning, according to their definitions, a reversable transaction because the funds came from a bank withdrawal.  Now, according to that definition, since any bank-withdrawal-based transaction is by their thinking "reversable", that would mean all bank-linked transactions would be "high-risk" and therefore Coinbase shouldn't even allow that option.

Of course, it doesn't end there.  ALL attempts at communication, through their site and through e-mail support are ignored.  You can open a case on their site, but of course the case is also ignored.  So I spent $291, Coinbase took it, cancelled the transaction, has my money and will not respond to any attempt at contact.

I've read lot of excuses for the lousy service by some Coinbase apologists here, but really, I'm a customer, Coinbase is (ostensibly) performing a paid service, so if their performance is this crappy, maybe they should find something else to (not) sell.