I was always told to never freeze weed, because freezing the moisture inside the trichomes and inside all the plant cells causes them to burst. When the frozen weed comes back up to room temperature, all the oils and esters volatilize and the weed smells really strong.....initially....and then it quickly degrades afterwards -more than it would have if it hadn't been frozen.
I might try it sometime, though, (if I end up with an expendable strain or an excessive amount of something), just as an experiment, but I've always had good results using the old, tried-and-true methods.