MyHeritage.com

As I continue to research my ancestry through DNA, using various tools and services, and gaining experience and perspective, my views of DNA services evolve. These are my thoughts about MyHeritageDNA, at this time, nearly three years into my DNA research. (Note: though I use the name MyHeritageDNA to distinguish the DNA matching service from the record searching service, both are accessed through the address myheritage.com, and the services are closely linked.) (Another note: MyHeritage is an Israeli company.)

Pros:

1) MyHeritageDNA has a large number of DNA contributors. Even though they are relative (no pun intended) newcomers to DNA analysis, they have allowed people to submit DNA analysis files from other services in order to quickly grow their contributors.

2) MyHeritage allows contributors to build family trees linked to their DNA, essential for exploring your relationship. While trees are generally smaller than what is available at Ancestry, in most cases you have full access to the whole tree. (Ancestry limits access to 5 generations, 23andMe doesn't have trees, GEDMatch does allow trees, though I find few contributors have them.) 

3) MyHeritage (currently) allows the use of third party tools that gather family tree data and DNA match data for exploration offline.

4) MyHeritage's list of common matches (ICW) also shows the relationship between the match and the ICW. This can be helpful in focussing your search for a relationship, or for selecting closer relationships to investigate. (For instance if you know that one of your ICW is a great aunt to the match you're reviewing, you can limit your investigation to the great-aunt's ancestor tree.)

5) MyHeritage has a closely linked (for pay) records collection, though I have never used it and can't comment on how it compares to other records services.

6) MyHeritage also owns one of the premier genealogy products, Legacy Family Tree, which is my genealogy software. While I know that Legacy has features that facilitate genealogy research, I don't use these features myself.

7) MyHeritage allows you to download your DNA analysis file, as well as match files. The former allows users to submit their DNA analysis to matching services like GEDMatch (I'm not necessarily recommending you do that). The latter allows users to keep track of DNA research offline using, for example, tools like Genome Mate Pro.

8) MyHeritage shows detailed information on shared DNA segments and which matches "triangulate", a much higher level of confidence of a family connection than the ICW relationships. (Ancestry shows only ICW. 23andMe shows both ICW and triangulation. GEDMatch shows only ICW, though I'm not sure what they offer to paid subscribers.)

9) Has an interesting DNA research tool:. DNA Clusters shows groups of related DNA matches. It used only about 100 of the several thousand matches, but as I identify more of my matches it is showing some promise.

10) MyHeritage ethnicity estimates seem as accurate as those from other services. At least compared to my own family history estimates.

Cons:

1) MyHeritage shows matches down to 8cM. Ancestry recently raised their minimum to 8cM as well. 23andMe seems to show down to about 7cM. For those, like me, with well-developed family trees, smaller amounts of shared DNA are needed to extend our histories. Smaller DNA matches are admittedly much less certain, but I have made several 6cM matches (at Ancestry before they changed their minimum match criterion) so far and would prefer to have access to these possible more distant matches.

2) MyHeritage flags are not very useful. I can neither set a flag (or star, as in Ancestry or 23andMe) nor read an annotation (as in Ancestry) to indicate that I have already connected a match to my family. In MyHeritage I have to open the attached note to know the status of this match.

3) For whatever reasons, I have identified far fewer matches through MyHeritage than through 23andMe or Ancestry. I assume this is mostly the relative popularity of this service.