Little side deviation that requires a separate post.
COATINGS
Uncoated cutters are Sharper, no and's, if's or but's about it, but loose the edge faster. Best for softer materials or where finish is the ultimate of importance.
Coated cutters are Duller, no way around it, during coating the side effect is rounding of the edge, but they last way longer. Increased hardness and wear resistance with a touch of sacrifice on cutting finish.
Trade off becomes, sharpness vs life vs finish and which has to most importance in your application.
Coatings come in different flavours, as long as none of the ingredients match what you are cutting, no issues.
Here is a list from one manufacture of the different ones (note there are more).
www.kennametal.com