Sceptical towards the quality of so cheap translation services, but i it all comes down to budget. I guess it is possible to do some QA before launching.
And personally, I dont need people with masters degrees to translate for me. I'd much rather have people with good marketing skills/understanding and a solid language.
We have a web app that two translators use initially independently to translate our entire corpus. The app then asks them to select the best option where there are mismatches (they can also enter a third alternative). There are a couple of rounds of this.
Finally an editor has access to all rounds of the translation in an editable table (http://i.imgur.com/zPJp0sz.png) where they can see who has inputted what, and wether things have been marked as 'acceptable' or 'completely wrong'.
This works well on most of our short/simple strings.
It also helps that we have two voice actors who are also native speakers come in and record the script, where any further errors or better translations can come up.
We do this because we're translating with different goals than the majority of translation purposes. We need to focus on translating for speech at relatively low volume and for those learning a non-native language. Most translation shops focus on written language for native speakers, high volume, speed and cost.