My German is perhaps a little rusty, but I can read enough to give you the review in a nutshell: DigiDeep Member Thomas Scheller upgraded to an NA-550D from a Canon G9 in a Patina housing. He looked at a few other brands but settled on the Nauticam and he seems very happy with it. He's impressed with the build quality, the locking latches, leak detector, port locking system, two stage shutter and much more. Sehr Gut!!
Read the whole review here, auf Deutsch
Or, take a look at Google's hacked up translation into English