I did a flat low and slow for my first and then did a flat with high heat the next time. I thought the HH came out much better and have never done another LNS again. I have done a couple packers HH too and find that is my preferred way for brisket.
Ray, the "whole packer" is the full brisket cut. Not entirely sure why it's called a "packer", but that's what it is. The high heat method calls for smoking the brisket at 325-375F as opposed to 225-250F. Check around the forum, including the link from Gary S in this thread, for more info about high heat briskets.