Manila mango does not seem productive at all here in Glendale. I got a grafted one 3 years ago (the grower said it was 2 years old when I bought it), 2 years in the ground but still cannot hold any fruit. It seems healthy and grows about 1 ft each year. Flushes new growth, plenty of flowers resulted in fruitlets, but all of the fruitlets drop. I will give it one more year before it goes to compos bin.
On the other hand, Little Gem (aka Little Jim) on Florida rootstock is very precocious and productive. Only 4 months in the ground (barely 1 ft, bought it online last March/April) but already held 18 fruitlets and all the fruitlets were growing. I took most of them off but leave 3 hanging on, so far they are growing nicely.
Pickering on Florida rootstock is the 1st year in the ground, flushes new growth and grow big leaves but no flower yet.