Bitcoin.de has I understand connect directly seller and buyer so every transaction need a bank transfer, that is not ideal, even if the idea is quite good for buying and selling
I think this kind of person-to-person transfer is optimal for switzerland because people can use SEPA. You need bitcoin.de only for BTC escrow what to me is an advantage.
mtgox sucks because you may fund your account with SEPA, but for withdrawal their bank does not support SEPA for switzerland so you have high fees for international wire transfer.