At the risk of upsetting the locavore community, I have to say that Alphonso mangoes are a really nice treat. I bought a case in Little India yesterday, along with a few Atulfo mangoes for comparison purposes.
I'm a big fan of the Atulfos, but side-by-side, the Alphonsos were noticeably better. I'm glad, because the case of 12 cost $21. Be prepared to eat them fast, because they're pretty much all in eating condition when you buy them.
As a side note...I bought a few decent cases of Brazilian mangoes at T&T throughout the winter. Then, stores (not just T&T) started carrying the Peruvian ones. I bought one case, and they were horrible. Just an FYI.