I have to say I am quite frustrated at the moment. I made a withdrawal of 3 real BTCs from bitcoinbuilder.com to my wallet two days ago and they still haven't arrived. Support emails I've sent were not answered so far.

edit: they finally arrived!

Josh's answer: "I apologize for that, there are some weird bugs in coinbase's send payment API it seems! I've re-sent the payment now, and for tonight's batch we are using a double-verification of the account logs to make sure everything went out that coinbase said did!"