Well, obviously if Germans didn't see value in IDN.com then they wouldn't have bought nearly all of them between 4 and 6 years ago! The country has over 80 million people, so the dot de namespace gets crowded real fast.
Try this test:
Using Google.de, I selected "Seiten auf Deutsch" (pages in German) - this also includes Austria, some of Switzerland, some of Belgium, etc, etc.
Search for
site:.de
http://www.google.de/search?hl=de&q=...a=lr%3Dlang_de
25.8 million results
--
Search for
site:.com
http://www.google.de/search?hl=de&q=...a=lr%3Dlang_de
24.6 million results
--
Search for
site:.net
http://www.google.de/search?hl=de&q=...a=lr%3Dlang_de
2.94 million results
--
To me, it seems that dot com is right on par with dot de for sites which are written in German language (for internal consumption), but they really don't like dot net much at all.
Now, this is where dot com really whomps dot de's ass - sites inside Germany which are written in any language (mostly english, for foreign customers, etc).
--
Go to Google.de, select "Seiten aus Deutschland".
Search for
site:.com
http://www.google.de/search?hl=de&q=...cr%3DcountryDE
79 million results
--
Search for
site:.de
http://www.google.de/search?hl=de&q=...cr%3DcountryDE
47.3 million results
--
Well, those stats are only useful if you trust Google's indexes to be accurate, but they do provide some sort of picture.
I also have development possibilities since I can speak German, unlike Japanese. German PPC also seems to be on par or even higher than Japanese - my experience has been that the average is about 5 cents higher per click (22 cents with German, compared to 17 cents with Japanese). CTR is also higher since Germans aren't all surfing with mobile phones. And you don't have to contend with that damned yahoo - I hate that search engine, it's like a freaking roller coaster ride.
.