"Takoma Plants are healthier more vigorous and more productive"
I noticed this too during the scion year and now as first year trees (not that any ripened fruit as rooted cuttings). So, I can concur on the apparent quality of Takoma Violet, at this early point. My observations and experience - of both this year and last year - of these same Mount Etna types match strudeldog's, though my trees are basically a year younger.
I can add a few other observed similar Mt Etna types into the mix: Black Bethlehem, Keddie, Salem Dark, Hardy Chicago... One caveat: Salem Dark may be somewhat more vigorous than Takoma Violet but Salem Dark for me at least so far has been among the least productive of the Mount Etna types. Again the caution, these are only the first two years of observations and experience of very young trees.
On similar criteria, currently I would give Gino's Black a slight edge over Marseilles Black and the others apart from Takoma Violet both of these past years.
It seems I am growing another apparent Mount Etna strain, unknown, that rivals Takoma Violet for both vigor, health, productivity but I'll know more about that over the course of another year or so. Similarly this ripening season should shine some light on the comparative taste of these young fruiters over the next month or so.