Is there a particular reason for the way these structures are represented?
There is no real difference. Sometimes this comes about from the drawing software people use or personal preference. In some texts the authors or typesetters are using LaTeX packages to draw organic molecules, this can be rather tedious and it is easier to use 90° angles.

The angled hydrogens are a bit closer to what a 2d drawing of the 3d object would look like, but not to the point where any information is conveyed. It can make visualizing the compound in 3 dimensions a bit easier for me when they are drawn this way.

For the double bonds the cis/trans or E/Z information is conveyed, although this is irrelevant in your example.