If you mean letting the Browser automatically translate the site then the multi-lingual content wins in each case. With automatic translation you dont have control of how the page translates, there are bunch of mistakes (especially between certain languages) and it may also breake your layout pretty good.
I stick to the fact thats its always best to have the content translated manually and having multi-language documents.
Or are you referring to automatic machine translations? http://devnet.kentico.com/docs/7_0/devguide/translation_services_overview.htm
This can automatically translate your documents and place it in its own document which is also better then having google autotranslate, because there you can see how it translated and you can adjust or edit the content afterwards.
If you have some specific questions, feel free to ask and we can discuss them :)