I am just getting started with DNA. What testing company should I use?

I have always heard two answers:  1. The testing company that your unknown relative tested with that will reveal your unknow 3rd great grandfather.  2. Test at all of them. If money is no problem, do the latter.  But DNA testing can get expensive. Test with a well known company, such as: Ancestry - largest database of autosomal testers and new tools for matching.  FamilyTreeDNA - offers autosomal test, Ydna test (paternal line) and Mtdna test (maternal line) has chromosome browser. 23&Me DNA - offers autosomal test and health tests, has chromosome browser. 

MyHeritageDNA  - Best test if you are looking for European ancestors, new tools for matching and chromosome browser.  Living DNA -  Focus on UK and European, just beginning matching.