Scourge Styles: Bats vs. Birds

In putting together my scourge squads, I'v always liked to delineate them based on wing type- bat wings vs. birds' wings. But I got to thinking: how are these different modifications viewed among the scourge cliques of Commoragh?

My thought is that bird-wings are generally more popular- the avian aesthetic is considered more striking, more aloof. However, I was reading an article about how bats are actually more efficient flyers than birds- they take less energy to fly due to their more dexterous joints and elastic wing structure. Perhaps those who take on bat-wings value performance over spectacle. I would bet their are many Scourge Eyries that have exclusively one or the other.

On the model, the basis of the bat-wings actually appears to be a second set of arms. Post-surgery flight is difficult for any Scourge embarking on their pilgrimage to join their Eyrie, but especially so with all those extra limbs and joints to master, so I assume fewer bat-winged aspirants actually make it up there (which lends to there being fewer of them in comparison to the feathered Scourges). Those that do, however, would consider themselves true connoisseurs of body modification, embracing the higher risk for the greater reward.

In the DE books, it didn't matter at all, and was a reflection of the individual Scourge's preference/idealization of flight (or whim of the Haemonculus performing the alteration).

Mine are all bird winged because they used to be ran as swooping Hawks (because the model is so much better and even at 2 boxes for 6 came out to a similar price point to the Hawks).
Then they became scourges when there was no cw codex and absolute zero reason to be Hawks instead of scourges. Then went back to being Hawks with the codex.
Now they be scourges again in as I've got a dark eldar.
I pretty sure they're having an identity crisis by this point