Google translation tool works only in a few cases

After last week's initial enthusiasm about the new Google translation tool, I decided to ask different people to check how the translation works out in their languages. I was able to investigate 14 different translations and the results do not look that good. For languages I do not speak I got help from my audience, most of the translations into English I checked myself.
Perhaps Google offers a huge improvement compared to for example Altavista's Babelfish, but in most cases the translations are not really usable.
What goes reasonably well, is translating Chinese into English, but the other way around is a disaster, for reasons mentioned here. Chinese has too many homonyms and Google gets only 50 percent right - and you have to guess what fifty percent.
The only good score - in both directions - is for Russian, other languages do poorly.
Philippe: "you have to guess from the context what it actually is supposed to say". German into English sucks, I concluded after trying to translated a chapter of my book on China into English.
Joerg Kilian thinks the service also sucks in German and retranslated a German translation into English of my entry on Chinese airplanes:

Not in the foreseeable future, I think. The condition gremium of China, the highest administrative organ, announced that the country would be ready for a larger commercial area (surface) for at least 150 passengers, rainsing the reported media.
After five decades development things were ready the official newsagency Xinhua reported. If I would be responsable I would let them try something more harmless like movable telephones.

I think it is the general problem. You could make sense out of it, when you know the original. But that defies the need to use a translation tool.
Mariab on Italian:

the translation of your blog in ITALIAN is quite inaccurate, actually in some parts is not really understandable. I think it works only for simple phrases with a quite linear structure.

Juan Pablo Cardenal:

translation into Spanish not good. Very confusing.

My advise: do not use it when translation is really important, the chance to create misunderstandings is just too huge. It reminds me of several situations where translators were not too sure about their own skills and just prayed nobody of the delegations they were helping would speak both languages. They are very good in holding up appearances. It is partly psychological: you want others to understand you, so you all too easy assume they do so.