I remember a story here a few months ago about a person who had deposited tens of thousands of dollars with Coinbase, and they refused to give the customer his coins. That was a clear sign that the systems and processes at Coinbase were broken.
The fact that they didn't help the customer until they took their grievances public indicated to me that either Coinbase don't care about their customers, or they were too busy trying to balance their books because of some proprietary trading gone wrong.
Thus I think it was foolish of Coinbase to release the letter condemning MtGox. Now anything that happens to Coinbase makes them look like total hypocrites. People, glass houses, stones etc.
It's one thing for a magic card trading company to morph into a Bitcoin exchange and have problems... but for a hot-shot start-up in San Francisco with self-proclaimed tech superstars at the helm and millions in the bank to screw up royally, well, it's just embarrassing.