I've been using TreeSheets for a long time now and, though occasionally I do run into limitations I find it generally to be on "the right scale" for nearly all of my needs.
It's small enough that it starts really fast. Simple enough that I can write, organise, and curate what little I have to deal with quickly enough that I don't give up or get interrupted midstream. And it works on most of the platforms I use. If it were available for my iPad, I'd buy it but I can totally understand not wanting to deal the iTunes store.
What's holding back a mobile port is 2 things:
1) It's written in wxWidgets, which has an unfinished iOS port and no Android port. Even if these ever get finished, mapping the UI 1:1 would probably make for a really bad mobile app, and would have to be adapted specifically for mobile. An alternative route is to rewrite the UI in Qt or OpenGL or something, but that's a huge amount of work.
2) It would need support for cloud storage.
It's small enough that it starts really fast. Simple enough that I can write, organise, and curate what little I have to deal with quickly enough that I don't give up or get interrupted midstream. And it works on most of the platforms I use. If it were available for my iPad, I'd buy it but I can totally understand not wanting to deal the iTunes store.