Exercise 2 solution (sample answer)

Roof prism: narrower and more compact, with the objectives in line with the eyepieces. Some roof designs (Schmidt-Pechan) are less bright than Porro at the same specification, because of mirror-coated surfaces.
Porro prism: Z-shaped light path, a wider body with offset objectives and eyepieces.

For a day of walking, a roof-prism pair is a reasonable choice because it is more compact; the trade-off is slightly less brightness in some designs. Any choice is fine if the reason ties to how you will watch. Check weights and prices yourself; the chapter gives none.