Are you worried about production at all or are you only focused on best tasting?
Sweet Tart is great because it tastes great, is vigorous and it’s disease resistant. Lemon Zest is one of my all time favorite Mangos but it can have issues with Powdery Mildew. Lemon Zest is also a vigorous grower and once it establishes, it will produce excellent quality fruit in years where PM is not too heavy. You can always control the the PM with Fungicides, even organic Fungicides like Magnabon CS 2005.
As for a top 5, I can’t come up with it right now but I can give you a list off the top of my head of varieties that I have considered to to taste phenomenal and also grows well here. ST and LZ already mentioned.
CAC, Kesar or Jumbo Kesar if you want a nice Indian resin flavored mango, PPK- perhaps a better alternative to LZ if you are worried about production, Piña Colada a small mango that lacks a big punch of flavor- very very sweet with great pineapple acid balance and a coconut nuance, Pineapple Pleasure in my opinion thastes like a giant Piña Colada but PP lacks the Coconut nuance.
NDM is not a flavor bomb but it grows great here, the seedlings is what I’m talking about, the grafted NDM #4s are slow grower here and I don’t recommend them. Valencia Pride is also not a flavor bomb but it grows well on Florida Turpentine rootstock and the flavor is good with a Coconut nuance when grown in SoCal. It is also very vigorous and disease resistant. I’m sure I’ll think of more later.
Simon