Never had any problems with coinbase, except when buying btc sometimes it says failed and takes money from the card little bit later. You could just always do this if you dont want to get tracked by them: coinbase -> wallet -> bitcoin mixer service -> wallet. Don't store your bitcoins there, withdraw asap to an address you own private key for.
The moment money arrives in the coinbase wallet,logically you give out your control to the exchange.Meaning,they can do whatever the fuck they want with the coins.If the sources of your coins is through a gambling site or any fraudulent practices ,your account will be suspended with no explanations. Why choose a complicated way to make your bitcoins secure when you can simply use a small desktop wallet?I do not mix my coins, but never had any problems when withdrawing to wallet and not to gambling sites. Also coinbase has lowest fees for me as i can get so im not changing because i've had a good experience with them.
created an account few hours ago... lucky me.