They look very similar (very much like 3rd from the left in https://upload.wikimedia.org/wikipedia/commons/d/de/Bananava...) when peeled (apart from size - they're generally 1/2 or 1/3 the length of an average Cavendish and a little fatter, relative to length) but they're much 'juicier' and probably a little sweeter too.
The taste itself isn't enough to put me off (see above about smoothies) but the texture is unbearable, it's like an over-ripe Cavendish.
Edit: for some growing-bananas-in-thailand trivia:
Here at least, the little horrible ones grow a lot faster and are much more durable than Cavendish. The tallest Cavendish plant we've had so far is maybe 2.5m tall - I can always grab the bunch when cutting them, and generally I can carry the bunch one handed.
The "Thai" ones are giant plants by comparison - usually 4-5M when they produce, and the biggest bunches I can't carry at all.
Then you have the giant Thai ones (the name translates as "Elephant banana") - the plant is as big as the regular Thai ones, but slower to produce fruit. The fruit itself are like a Cavendish on steroids - easily 2x the size, but horrible to eat, not even any good for smoothies. Even my in-laws don't know anyone who actually eats these ones.
Then there's the even tinier Thai ones (the name translates as "Egg banana") which have a quite short, but very leafy plant (maybe 2-2.5M tall at most) with lots of offshoots. The fruit itself are tiny - most plants here the bunch never drops down to 'hang' because it's not heavy enough, and the bananas are, as the name suggests, comparable in size to a large chicken or duck egg, and almost egg shaped too.
Thus concludes my tale.
maybe LA shoppers are just lucky, but i've seen plentiful alternative varieties in grocery stores here, including "Cuban/Jamaican Red", "Thai" (a little bit like Hawaii's "Ice Cream Banana"), and "Burro." they usually taste better than the Cavendish. and, on sale, you can get 3 pounds for a dollar.
i occasionally see fruit-bearing banana plants growing in Los Angeles itself. i've tried some of these and they also taste better than the Cavendish.