These are my favourite packing cubes. The quality is much better than cheaper packing cubes I have owned in the past. The fabric is thicker and the zips are smoother.
The large cube is big enough to fit all the clothes needed for one person for 3 nights. It has a handy compression zip so there is plenty of space to fit everything in, but then it zips down to take up less space.
The smaller cubes are also deceptively spacious. I haven't used them for shoes yet, but my kids were able to fit all their clothes and pyjamas into one shoe cube for a sleepover, and they took up very little space in their bag!