I agree with the above posters.
Now one could certainly make the case that they prefer the DL model of an enhanced-economy product, but I suspect very few (if any) people would prefer DL over AF for the same price.
There are lots of different enhanced-economy products out there. Each have their own merits and drawbacks. The AF model of improved seat/service/catering is the 'best', except on price. The UA model of only increased legroom offers the least to the customer, but can be offered for less money. There are various models in between. I suspect people's preference generally comes down to their willingness/ability to pay.