Ask HN: Which translation API?

Given the recent announcements regarding API shut-off's (http://news.ycombinator.com/item?id=2592399 is one of several posts on this), I expect many people are in need of a good translation API.

From a quick look around, myGengo is out because of the human element and therefore pricing. My particular site will have lots of property listings added daily (perhaps up to 5000/week). MS has http://www.microsofttranslator.com/dev/ but I haven't yet had a chance to look it over.

Are there any others of repute? Paid is not a problem but "good" automated translation is essential.