Coinbase is a giant scam. I have bought and sold to them succesfully many times, but just today I tried to buy .5 BTC and they automatically cancelled the transaction... I then got a nice e-mail saying how they'd refund me the money in 3 or 4 business days.... WTF .... they can take my money before cancelling the transaction??? That is criminal.. Do not do business with Coinbase or this may happen to you too.
Of course they are. All they have to do is rip off a small handful of the 700,000 customers they have to make a gigantic profit.