Alphonso is more hype than fact, reason being 90% gets exported out at very high prices so what is left folks brag about how good that is, mostly locals, no different than folks buying Louis Vitton purses and feel good, there is nothing about it than the name and high price tag.
I have eaten the top Indian mangoes and grew up eating them in India. Kesar hands down beats Alphonso, then there is langra, imam pasand, dusseri, bengalpali, gulab khas, and few others that compete equally or even beat Alphonso, which also has spongy tissue problem.