I guess it depends on who you talk to. I have contacted several adult Colombian adoptees about this issue. At least three of whom had pursued this type of testing and were willing to share their responses.
Here are their opinions -- luckily they kind of ran the gamut:
Adoptee #1 stated, "I have done the third kind of testing and it broke down exactly as you said - 4 groups and tells you the percentage of how much you are of a particular group. I was actually a little surprised at my results. I thought though, it might bring me some insight into myself, some peace perhaps, but it really didn't. I almost don't believe it. If it came out of a relative's mouth, then I might."
Adoptee #2 found it helpful, especially when searching for relatives and siblings, "My DNA is now in FamilyTreeDNA's database. I am a member of the "Adopted" project...I haven't found any relatives yet. Hope is alive, though. :)...I know there's been at least 1 set of siblings who were adopted separately from Colombia and found each other through DNA testing."
Adoptee #3 found that it gave her a sense of identity, "I knew so little about my birth and my birth family. It was like a big question mark. I was from Bogotá, Colombia. That is all I knew. Now, I can at least think I am part this and part that. It connected me to my roots and filled part of a void that I feel."
Well, the test's validity is only as good as the group they have to compare you to. So, for example, if I am a direct descendant of the Chibcha Indians, and the agency running my test has NO Chibcha descendants in their database, I may get really weird and not completely accurate results. (This is how I understand it at this point).
Therefore, the more people who add themselves to the database, the more accurate the model will become.
In researching for this blog, I found that perhaps the best choice might be Family Tree DNA. Here's why: They have a Native American Ancestry group and have Colombian indigenous groups in their pool. Having indigenous Colombian groups would likely be important in determining your genetic heritage. They also have the Adoptee Project mentioned by Adoptee #2. Additionally, they have large European databases -- think Spanish Conquistadors.
However, before you haul off and send your sample to Family Tree DNA, you should also consider the National Geographic Genographic Project. Their results will only show your REALLY DEEP GENETIC Ancestry. You'll get a map of your genetic family's earliest migrations. If you have NO DESIRE to link yourself with others who share your common nearer genetic relatives, this would be the way to go. Currently, they are trying to promote their program to Latinos. http://www.nationalgeographic.com/genographic can provide a more accurate description, if you want to read more.
Adoptee #2 also mentioned the following about this test option: "Their Genographic project is designed specifically to help map the migration paths of humanity. The cost is about $107 including the shipping and the initial processing of the DNA. They have their DNA testing done through an agreement with Family Tree DNA, who also offer additional tests beyond what the National Geographic tests are looking for. I've had the initial test done, and am pondering having all the tests run. If we had enough people interested, with results in the Family Tree DNA database, we could probably have them create a group, for Colombian Adoptees, which could increase the chances of adopted relatives finding each other. " Definitely gives us something to think about.
The last option, and really, I am not sure how much to recommend them -- is DNAtribes. They have several hundred Colombian samples -- from Boyacá, Bogotá, and Caldas. I would say if you were not born in one of these areas you should not choose them.