Best by test
When I first began to grow Meyer lemons in Guatemala, my family and friends told me that Guatemalans preferred the Persa lemon (Persian/Tahitian lime) or criollo lemon (key/Mexican lime) because of the more tart flavor.
I said, people who "prefer" other lemons either do not know the Meyer, or cannot get it. Two weeks ago one of my two Persas at my Meyer farm finally began to produce after 5 years (my Meyers give you harvestable fruit in 18 months). My wife asked me to bring some to the house; because some people preferred them. I brought 30 lemons; and after two weeks they are drying/rotting on the counter... no one has eaten a single one. Why? Because they have Meyers. In my home garden I have a Persa at the side of a younger and much smaller Meyer; the Persa, after 5 years produces less than 10 fruits per year while the Meyer produces more than 100. Next week the Persa comes out to be replaced by another Meyer; that will make 3 in my home garden; and even though Guatemala is a hard core lemon culture (lemon on EVERYTHING), we will never have to buy another lemon.
The last time we sent Meyers to Berlin for the Fruit Logistica show, a world famous chef told the media, "When I can get Meyers, I don't even consider another lemon in any of my kitchens. In Guatemala today not one of my friends or family eats any lemon besides Meyer.
Once you know the Meyer, no other lemon will ever be good enough for you.