The description has been pretry well covered. To summarize 8flavor, if you like the zing on an intensely sweet mango, then go with Sweet Tart. If Sweet Tart has too much flavor or you dont like that zing, go with Kathy. If you were to taste ZINC, Sweet Tart and Kathy together, you would be able to discern the relationship. Kathy could almost be described as a ZINC with a blend of Sweet Tart flavor minus the zing. All 3 are great mangoes when full mature and ripe.
I might say that it is more medium plus vigor to the lower end of vigorous. .