Prisms or mirrors for beamsplitters & why?

Since either of these can be used as a beam splitter, why do some manufacturers use prisms while others use mirrors? Are there any advantages or disadvantages to either method? Which are more expensive to produce? Are both systems equally robust? Do they have similar transmission specs?

A partial mirror used as a beam-splitter will exhibit ghost images on bright objects which is why they are not generally preferred for astronomical usage in binoviewers.
Scotty