Another advantage of Oruxmaps is that you don't have to download multiple zoom layers like you do for the others. You can "software zoom" in out out from that one zoom layer which means that the maps will take up a lot less space on your sdcard. This way you will have enough sdcard space to download a topo map that covers a much larger area.
Downloading maps at *only* zoom level 15 works for me. I can then zoom in and out to other levels with Oruxmaps.