I’m using Memmy on iPhone/iPad. Not that that helps you currently. I know the Memmy dev plans to make a android version. I think once the iOS one is out of beta.
Different developers. Memmy has an actual iPad mode that MLem so far doesn't have. I feel like the each miss or have different features that the other has. I guess its all down to feature to do lists being different in terms of order. I prefer Memmy over MLem at this point, but I use my iPad a lot for reddit and now this.