Can some one enlighten me as to when I should use either of these props.

I don't think it really matters, but is just a personal preference about which one looks nicer for you.

The first look video says that both are about equally common on the C441.

I woud use and test both....    What the hell...its about flying!   They are all good...    My impression, MacCauley is widely used.... but may be....feel like you like the other.....  So go and test it!...