After reading up more on speeds and feeds, I also dived into coatings and what their purpose was.
From what I understand, depending on the coating, you can cut different materials more efficiently. The reason you wouldn't want to go with a coating would be price, and you can't sharpen the coated carbide endmills meaning they are a one time deal.
Since I mainly cut in aluminum, I primarily focused my research there. Aluminum has a shallow melting temperature (compared to say steel), which means you want chips to be evacuated quickly and smoothly; for this, you'd want a smooth surface finish on your endmill to cleanly cut and remove material. From what I found, TiCN or titanium carbonitride was recommended for cutting soft materials like 6061 aluminum, so I ordered four endmills.
I got a 1/8" two flute corner radiused, 1/16" two flute corner radiused, 1/32" square two-flute, and 1/8" four flute ball endmills. I will be testing these soon by making a new clamp/vice system for the Pocket NC, similar to what Winston Moy made for his machine.