A few opinions on aluminum blades.
As Corey points out, most metal training blades are pointy, so the choice of the model is important. For longer blades, I've found that a point is less of an issue than for shorter blades, mostly due to increased difficulty of keeping a longer blade stable on a thrust. The real "killers" have turned out to be some extra pointy Spyderco replicas. Ouch ! Just put one in the hands of a first timer, and you'll have a chance of feeling a full force #3 thrust. Consequently, on request, Bob Burgee made me some great mirror-polished short blades with a near semicircle in place of a point. In generla, aluminum blades are completely unsuitable for sparring unless you have a full face mask, such as a fencing mask. The grill spacing of the WEKAF helmet won't stop an Edges2 Fighter or other long/thin blades from reaching the face, and particularly, the eye.
The appearance of the sparring blade, I believe, is an important component of the experience. We don't pick up a hair brush for blade practice, so realistic construction is obviously important. There is something scary about the flash of metal, and that fear is important to the sparring experience. I think that fear of metal is also expressed by choosing plastic. Sharkees are great for regular practice as they are simply safer and cleaner than aluminum. Nonetheless, I think the aluminum models (I like the Edges2 Fighter) help with edge awareness, and the narrow/flat construction offers better feedback that will help avoid the "blade smacking". I've seen a lot of blade sparring , and it's common to see someone holding the aluminum training blade backwards, with the unground edge used to make cuts. If a reflective plastic process existed that could compete with the cost of a grey plastic, more practice blades would be made this way. Granted, there are some training blades that are made to appear as if they are not real.
The Gathering is a showcase for weapons fighting, and thus we also have a responsibility to properly communicate the expernience over photos and video. The uninitiated can easily recognize the power of the stick. The rubber or plastic knives don't do a good job of communicating the experience over video. "When I saw that black piece of rubber coming at me, I peed in my pants." If the audience is unable to recognize or even see the knife, then it will be difficult to communicate our real contact fighting. Aluminum blades look real on video, and both the fighter and viewer experiences are a bit more genuine.
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