I never had a mango until I visited Mexico in 1987. I bought one from a street vendor, and just sunk my face into it. Wow! If a mango is perfectly fresh, it is an almost euphoric experience to eat it.
Mangoes do seem to range in taste. I don't know how you determine which varieties are the best, but I just buy one whenever the price seems reasonable and have it ripen on my kitchen counter. When the flesh yields to pressure, it is ripe.
Cutting up a mango isn't trivial. I found a small website that has a great set of instructions for how to cut one up:
Don't worry about buying organic mangoes because their tough skin protects them from pesticide contamination. They are a good fruit to have around because you can buy them at the beginning of the week and eat them when they are ready. If it softens before you are ready to eat it, just put in your fridge and it should stay good for a couple more days.