I think another big con of these tests (at least at the moment) is that they're either relatively expensive and incredibly inacurate, or incredibly expensive.
I remember reading about a guy who sent his DNA off two half a dozen different 'sequence your DNA' centers only to find that each one sent him back different results.
He then sent his dogs DNA to them and only 2 picked up that it wasn't human!
Yeah, i totally agree with you because 'cost is in direct proportion to quality' not only for these tests but also in most of life situations.
But i believe that the steep drop of about $2.7 billion to sequence the first human genome to about a range of approx. $100-$3000 for present day genetic testing indicates the possibility of better and much more improved test quality at even cheaper costs in the nearest future
That would be awesome, you're right!