Hello all,
I am a heavy translator on WikiMedia projects. I would say more than 95% of my contributions on content is translation. But I am against a blind translation. For example mostly I would translate british or north american related content from en-wp to zh-wp, and not from other languages. I would translate german or general european related articles mostly from de-wp to zh-wp. French related articles I try to translate from fr-wp to zh-wp, mostly I would make a test beforehand that the language in the article is enough comprehensible for me, since my French is by far not on the lever of my German or English. But I would never translate a Japanese related article because I don't think quite trust what the German or other english speaking people write about Japan. I never translate a China related article because I am very sure that at some point they have a not correct context. Even if there is no article in zh-wp about that particular entity I would rather wait a zh-wp user who has more understanding to start an article on it. (Or, ocasionally I would do research myself and start an article from scrap.)
Natural science related articles are sort of universal, although reading through different languages you can also find here tremendous differences between different language versions. I used to select the (in my subjective opinion) more better version (before 2006 more en-wp, in the last two three years de-wp or en-wp about half half), or I would combine both versions.
Backward, I would only translate China related article from zh-wp into de-wp, because I think the deficiency in de-wp in this area is the biggest. And some zh-wp articles, especially the excellent aritcles, are really very well written and researched and source. I don't see any sense to translate a German related article from zh-wp to de-wp.
Translation should never be blind. For example en-wp articles about american towns and cities could get very detailed, down to neighbourhoods. I mostly omit too detailed parts one because I would start to do original research beginning to invent Chinese transcriptions for the names and second I think they are not really interesting for a Chinese user. You can also find all kinds of failures in the original article, if you are doing a blind translation, in the best case the failures remain in the original article, in the worst case you propagate those failures into language versions that maybe have no resource to check those facts. For example in the article I am currently working on [[:en:Mumbai culture]] there was the failure that the city has three World Heritage (actually there are only two on its territory). Most failures are wrong links because of articles got moved or disambigged and the links didn't got corrected. For example in the article mentioned above in the section Cinema Multiplex was linked to [[:en:Multiplexing]], the correct link should be [[:en:Multiplex (movie theater)]]. Such errors are quite common.
Doing more careful and considered translation can help both language versions, more than simply doing a translation.
Greetings Ting