From what I've been reading I'm inclined to put more faith in GedMatch than any of the others. Although I've yet to understand exactly how that site works and what it can tell me. I think any Celtic I have would more likely have come from Scotland as my grandmother and her family were Sinclair. But that's why I took the test - I'm trying to trace a Sinclair ancestor. However, I can't do a Y-DNA, or mtDNA, test separately as I don't have any male (or female) relatives living. So, on that side I've hit a brick wall.