In a relatively old post on his XML Aficionado blog, Alexander Falk critics Google Translate's performance translating German to English, and concludes that machine translation in general, as it stands, is of no practical use.
I beg to disagree. While machine translation is rarely flawless, I have found it suitable to hand the bulk of translation works – leaving me with the much lighter tasks of reviewing and editing the resulting text. The last two posts on this blog, for example, have been translated from Portuguese with the help of Google Translate.
And even on one occasion, it served me well enough in translating a text – a technical reference that seemed to be the only one of its kind – from German to English. Notice that I don't know German at all, yet the translation, while by no means pretty, was intelligible enough that I could grasp its contents, and later use what I learned to solve a bug in a software I was developing.
So, imperfect as it is, machine translation already proves itself a useful tool.