Translation Company - Choosing the best one

If you purchase almost any kind of online service- freelance web design, consulting services, online marketing, etc – these can be evaluated based upon the results you get, and your experience with the service.  You're able to decide if the service was useful; whether the service delivered what was promised, and if the quality was consistent with the cost.
But what if you need a professional translation?  How do you know if you are getting a good translation?  Or even the right language?  How do you evaluate a translation company?
A translation company provides a service that most of us can't evaluate like most other services. We can't look over a translated document and decide whether they did a good job, or whether it's a disaster, when we don't have a clue what we're looking at.  This is why looking for a translation company to translate a business contract, a website, or legal documents can seem bewildering.  How can you tell if a translation company does what it says?  Which ones can you trust? How do you know if you're getting an English to Greek translation or just jibber-jabber?  
You don't have to blindly choose a translation company and hope they get it right.  Below are a few methods for deciding upon and evaluating a translation company
1. Translation companies are generally a safe decision, over individual freelance translators.  A translation company found fairly easily online has to work to become established - especially with so much online competition.  They invest in their reputation through customer satisfaction and competent translation.  It's much more difficult to verify a freelance translator's service quality or previous experience, apart from what they claim.
2. Use translation companies whose websites have obvious history (for example, blog posts from 2007).  Also consider that translation companies on the first results page of a common translation search (professional translation, Latin translation, translation services) have invested in establishing trust with the general online community.
3. Have your translation proofread by another translation company.  Proofreading is the best way to evaluate a translation company's services – a “second opinion.”  If there are many problems found by the proofreading company, have it proofread by a third.  However, do not expect two or three translators to perfectly agree upon every word.  Three different translations could all be perfectly acceptable, because much is determined by the translator's best judgment.  There is no single perfect translation of most texts.
4. If you have a friend or family member who speaks a foreign language fluently – French, i.e.- use them as a proofreader for a preliminary translation of one or more companies.  Have them evaluate the translations as part of your selection process for a professional translation.
These suggestions are in no way infallible selection strategies – but they are certainly better than blind selection.