what is the best method to share data across parts?

usually, I model one part and then when I want another part that shares data (outline, screw bosses, etc.) I will create a new part and the first feature is an insert part of the base part. sometimes this base part is a master model part and other times it is just a single representative part.

I know another way that you can do this is to create the part in context of an assembly and then save it as a unique part. 

what are the (dis)advantages of using insert part versus creating the part in context?

i seem to recall having issues doing in context stuff in the past but honestly, I've just used insert part for so long it may just be that since that's how I learned it I just always use that method.

just looking at alternatives and pros/cons

thanks