I personally belive in elevated feeding. I believe that it helps reduce air intake (which helps reduce bloat), that it helps prevent water spillage, and that it just looks more comfortable. For my saint zoey, elevated feeding it crucial because it hurts her hips to bend down (she has HD).
But at the same time, for every article you read saying elevated feeding prevents bloat, theres another that says low feeding prevents bloat, etc. So if one dog seems more comfortable laying and the other standing, I would get an elevated feeder for Zoey and keep Dolly's on the floor