The time it takes your DMOZ listing varies greatly by category/editor for that category. Editors of smaller, less competive categories can sometime respond within a few weeks, but this seems to be the execption in my experience. When my listings have been included, I can say that it has made a difference. Some editors, especially of very competitive categories get burred in submissions. It does not hurt to submit to your second choice category if the first one does not pan out. You could always volunteer to be an editor if you have the time and feel like you would have something to add to the category. Good luck!