I imported into Geni a GEDCOM file just exported from MyHeritage.
The file starts with:
0 HEAD
1 GEDC
2 VERS 5.5.1
2 FORM LINEAGE-LINKED
1 CHAR UTF-8
1 LANG Russian
1 SOUR MYHERITAGE
Geni ignores the Language field. All the names, which happen to be in Russian Cyrillic, are in English language tab in Geni. It looks like I'll have to add a Russian language tab to each Geni profile, move the name field, and (if I'm not lazy) add an English translieration.
Many profiles in the Gedcom file contain:
1 DEAT Y
2 DATE ...
2 PLAC ...
2 CAUS cause of death
Geni just ignores the CAUS field when importing the GEDCOM file, but correctly loads the date and the place. I guess I'd have to copy them over manually as well.