found some info about the Royal purple flavor...sounds like a mango I want to grow...but let me eat one first...then I can make up my mind...I find a good grape taste to be something of rare occurrence.
http://centralfloridapalms.com/fruit/mango/mimangovar.htmAustin
Little fiber, tart, citrus aftertaste, good
Very large tree, purplish, huge fruit, weird bumps, cross between Kent and Royal Purple, and found as a volunteer under a Haden, shy bearer
Royal Purple
Excellent with grape aftertaste
Large tree, fruit looks like hanging grapes. Small fruit, palmsize, dark Concorde grape skin.