I'm currently a firstie, and I've used both the Khybers and Garmonts. Trust me, the Garmonts are by far the best boots on the boot memo. Everyone shows up with a random assortment of boots, and by the time people are firsties a good half of the class is wearing the Garmonts and no one wears the other two types of boots on the boot list. I used the Khybers for my beast, and they were pretty awful. They also tend to fall apart pretty quickly. From an aesthetic point of view the Khybers also make you look like the Michelin man (not desireable).
Trust me, just go with the Garmonts.
edit: Overall though, don't worry too much about breaking in whatever boots you get. Breaking in your feet is really what you want to do. The boots don't need too much breaking in, but your feet need to become tougher. Blisters are the big problem if anything for New Cadets.