I tried withdrawing ~5 btc from Mt.Gox yesterday. It stopped saying the address was invalid (it was giving me that error before when I tried) and took the money out / claimed to process the transaction. That said, over 24 hours later and nothing has shown up on the blockchain. I sent in a support ticket earlier today. I've had my share of problems with Mt.Gox before, so I don't think that my btc is gone for good. While I feel like they're quite incompetent, I don't think they're trying to outright take our money away from us. That said, once I get everything out of there, I'm done with them for the foreseeable future. I know people have been experiencing issues with Coinbase, but it's not nearly as many as with Gox. I've had some success using it so I'll use Coinbase for now.