4 ohm or 8 ohm?

[Ronson Hall]

Folks,

I've convinced myself that, since I have an Eden amp (Traveler Plus) and look to get into another Eden amp soon that I should make sure my future cabinets run at 4 ohm, as to maximize the power and performance output of the amp (they seem to do their best at 4 & 2 ohm loads).

However, I admit that I don't know why someone would choose a 4 ohm cabinet over an 8 ohm, other than to match it up to the amp they already own, or plan to own.

Question: Why 4 ohm or 8 ohm, other than the reasons I've listed?

What are the major differences and advantages between the two? Educate me, Please!