So, I've read various articles tonight about bananas...
TL;DR Version: Are the flavorings in e-liquid generally emulating Cavendish bananas or Gros Michel bananas? I wouldn't know because I'm only 26 and I've never had a real Gros Michel in my life. Was curious.
Quick Banana History: Those banana-flavored candies out there are much more robust in flavor because they are emulating a near-extinct breed of bananas called the Gros Michel, which was nearly wiped out due to Panama Disease, a lethal fungus that effects the banana leaves, a few decades ago. The more bland banana that were are used to today is a breed called the Cavendish (also due to be wiped out in the next decade due to a new strain of Panama Disease).
Artificial banana flavoring is mostly isoamyl acetate, which is the most prominent note in bananas but not the only one which is why it can get banana runt-ish by itself. Little closer to an overripe Gros Michel, which you can still get if you happen to be in Thailand and has a more single-note taste.
It's not based on either. It's just cheap to build the component esters.
I've have 2 different bananas and they're pretty much one of each type. The first banana I ordered is from Flavor West. It's much like the more natural banana flavor like in desserts and regular bananas you find in the store. Then I ordered the TFA banana and it's just like a banana runt. I don't particularly like the TFA banana as I've yet to make a great juice based from it. The Flavor West banana is a lot more versatile, to my palate at least, so I use that one almost exclusively now.