I actually saw a major advantage of MtGox in dealing with the fiat payments. bitcoin.de is just a market place, not an exchange. In a sense GOXes .6% are cheaper for what is on offer than the .5% from bitcoin.de. Yes, they have some safeguards in place, but still, if something goes wrong in the line of an unauthorised account use, it is yourself who has to deal with it.
Unfortunately the whole discussion is kind of pointless as GOX is currently not providing anything near to be called service. Simply not handing their customers money back renders all their nice features useless.
Exchange means they hold everything. Market means they only hold the BTC you are trading. I don't want anyone holding my BTC or fiat for a second longer than they have to because when it comes down to it many of these places have got hacked, or collapsed overnight. Tradehill, bitcoinica, the polish exchange that wiped its wallet.dat, that big GOX hack, and so on.