(Disclaimer, I am not Wiccan, most of the people I have been discussing this with are not Wiccan, so take that into consideration for this post.)
I've seen a lot of interesting comments going around the last few days. A few people who have never used a ritual knife, a few people who used them but stopped (generally in favor of wands), and then even one guy who said he couldn't imagine why anyone would need a ritual knife unless they were going to preform an animal sacrifice. Really.
I think it's quite interesting that so many people seem to favor the wand over the knife, when for me I've found the opposite to be true. I have no wand, no need for a wand, no desire for one. When I see a lot of people making the decision of one over the other, it usually comes down to the tool's ability to direct energy. What feels "nicer" and, well, "less scary" is sometimes the term used. In this aspect, I have always preferred the knife. Perhaps because it feels more precise to me.
But the real reason I continue to have a knife is, well, I need to cut and carve things. I know that's often a no-no in Wicca, but I am surprised how many non-Wiccans don't seem to take this function into account, or just don't need it. I use my knife to gather herbs, twigs, carve symbols, cut cord, and so on.
Beyond that, because I often hold my workings outside, sometimes far from home, I try to keep the number of things I need to a minimum, and I try to choose tools and items that can preform more than one function. So, for me, the knife wins out over a wand. It not only does the ceremonial functions, but it also does the more mundane things one would expect a knife to do. Which, anyone who has existed in the world for any length of time, knows that knives can do a lot of things that aren't animal sacrifice.
"But you can't just stroll around with a knife to a ritual site!"
Well, actually, I live in New Hampshire so I can do exactly that. Thanks New Hampshire for basically having no knife laws.
Now another concern I've seen makes a bit more sense to me - Fae are said to dislike iron (and so, also steel). I don't really use a lot of tools when honoring and working with the nature spirits, so this hasn't yet been an issue for me. Some also feel the wand better resonates with their deity. For me, and the deities I work with, knife again tends to make more sense.
I have also encountered the idea that metal isn't natural. Won't even wear jewelry during a ritual because it's not natural. I am not sure where these people think things like iron, gold, copper, etc, come from...
I realize it's all quite personal, and I'm not writing this to get people to "convert" to using a knife or anything, these are just the reasons why the knife is a much better fit for my practice, and why the wand was left behind with Wicca, way back when.