As for MyHeritage.com, for the U.S. it has little for before the 20th century, and pre-20th-century material is largely (or completely?) available elsewhere. Much depends on where a researcher is in her/his research.I must say immediately, that I heartily disagree with the comment's conclusions. I cannot imagine this comment coming from someone who has used the MyHeritage.com program the way it is designed to be used. I am not even sure what the commentator is talking about.
MyHeritage.com is primarily a family tree hosting program with extensive family/social networking capabilities. Its automated research capabilities are based on its programmed Smart Match, Record Match, and Record Detective Technology and fully functional only when the user (member) has a full subscription to the program and has uploaded or entered a family tree. Using this technology, the program begins to search for connections with other users' family trees and matches the individual ancestors who are the same person. This technology is very accurate in establishing relationships and we have had some remarkable experiences in connecting families.
The Record Matching and Record Detective technologies are equally amazing. They are extremely accurate in identifying pertinent source records which can then be easily attached as sources to an individual or family. If the commentator did not follow this procedure, then it may be understandable as to why the comment was made. If you simply use MyHeritage.com to search for individual ancestors, your efforts will be no better than your own ability to search and usually about the same as any other online genealogical database. I can see how some people may be disappointed in the results of their own searches. If you want to research an individual, you need to do that from within your uploaded family tree. You will find the records much more pertinent if you search from ancestors that already have attached sources.
Now to the complaint about the content. No one is very impressed with a database that does not seem to have the record you are searching for. That is the same criticism that can be made about any or all of the online genealogical database programs. But the comment about the limitations of the records to the 20th Century are what indicates to me that this person did not use the program as it is intended to be used. Many of the U.S. records found by MyHeritage.com for the ancestors in my family tree date back into the early 1800s or much earlier in the U.S. The U.K. records go back to the 1500s. Danish and other Scandinavian records go back to the 1600s. Very early U.S. records have generally yet to be indexed and therefore they are not usually available to search engines. I have been waiting for Town Records from New England to appear online and I am still waiting. This is not at all a limitation of MyHeritage.com. As they acquire newly indexed databases, those records become quickly integrated into the superior search capabilities of the program.
What about the availability of the records elsewhere? That is an interesting criticism. I guess my response to that is so what? Do you want the help of the MyHeritage.com search capabilities? I certainly do and the fact that some of the records are in other online programs is meaningless in that context. In fact, many of the newly added records come directly from FamilySearch.org which is just now beginning an automatic search program of its own. As for me, I am grateful the program does its automatic searching of records I would not have time to search on my own. Many of the same records are in all four of the larger online database programs, but each also has its own valuable records.
The fact that any one or all of the programs do not yet have the records you are searching for has no bearing on the value of the programs. It is also entirely unfair to dismiss a program as only useful for "beginners" when the program may have records that you may never find now that you have that attitude.
One of my opinions is that MyHeritage.com is not used enough by older, more experienced genealogists just because they do not understand how it works and are unwilling to put their family tree online in "another database program." They then lose out on an extremely valuable program.