I'd recommend you read up on the history of Google Translate. There are some interesting interviews with the guy who coded it (he was adamant it would never work).
Fact is this: Google has the largest database, on top of the UN document that formed the Rosetta stone of autotranslation, plus they are the most widely used, so they can datamine error reports. You will find better translation services out there, but they are just that, services. You pay money, input the text and get something back in some time from a living, breathing human.
Also, if trying to gauge how useful those services are, again, you'll fall flat, as the algorithms are inconsistent. There is a grammatical based set of algorithms they can fall back on I believe, but for the most part if translates from memory, through data mining. This is why dropping a fullstop basically kills the service.
Check out Translation Party and notice how the funniest ones change almost daily as the algorithms adjust to the latest database.
