I feel that the Packer bar is adventageous for its overall size/coverage, and I feel, a bit mroe total compaction which (again, I feel) sets up harder and helps establish a base on which to drive when the next snow hits, and not pull up dirt/rocks as easily.
The advantages of leaving the surface tracked is that it is a rougher serface with more and deeper texture, and is better able to catch and hold snow when the wind blows.
Others may have more opinions, but those are mine.