Yes, I have had an Ancestry dna test and am very dubious about the results. Their initial assertion was that my dna was 96% English, 2% Irish and 2% Scandinavian. although the Scandinavian bit surprised me slightly I reasoned thar it was so small as to probably date back into the mists of time. The Iriash component seems to have come from my father's maternal grandfather
Over time Ancestry's estimates changed. I lost my 2% Viking and a couple of percent English in favour of 4% northern European, which I considered reasonable as their database grew and became potentially more accurate.
Then, recently, my belief in Ancestry dna tests was blown right out of the water. I had my Scandinavian dna back, this time ascribed at 3% to Sweden but my English component had plummeted to 70% along with a Scottish estimate of 25% and 2% undefined.
I have been researching for about 20 years and have identified all of my ancestors as having come from Warwickshire and Leicestershire right back to 1640. I have over 12,000 names on my tree, not one of whom, so far as I have been able to determine, has ever set foot in Scotland, let alone been born there. Furthermore, a figure of 25% would appear to suggest a fairly recent Scottish ancestor and I can be absolutely certain of the English origins of all of my grandparents, great grandparents and several earlier layers of ancestry.
Just to make matters more interesting, the original information provided ny Ancestry even got my eye colour wrong.
All of this said, the test has proven worthwhile as it has connected me with a wide variety of hitherto unknown relatives, many of whom have been able to further widen my knowledge.
Keith