By now you have probably seen Guy Windsor’s Plastic swords are for children. My counter-argument is this:
Reduced speed drills are detrimental. I don’t think they are merely useless, I believe that they actively hinder the learning process. When working at 1/2 speed or less you cheat timing and momentum. On many occasion I’ve seen a technique appear to be correct during a drill, only to discover that it is deeply flawed when performed at full speed.
Now I’m not saying that you should never work below full speed. If it helps, by all means start slow. But by the end of the drill you should be moving at the same speed you would be using during free sparing.
Now on the topic of simulators, I would love to use steel. But as of yet, no one has recommended to me a steel simulator that is flexible enough to safely throw thrusts while sparing at full speed. Hanwei’s Practical Hand-and-a-Half Swords and a good pair of gauntlets may be safe enough for cuts, but I wouldn’t want to take a gut shot from a careless thrust.
And of course there is the problem of gauntlets. As the amount of protection they offer increases, your flexibility in the hands and wrist decrease. Complex actions such as molinellos are just as much a part of unarmored longsword as they are in arming sword or rapier. So to be true to the system, we should be using as little hand protection as safety allows.
Now I’m not claiming to have tried every steel longsword simulator on the market. If you know of a sword that is both accurate and safe for sparing with thrusts, I would love to see it. But if forced to choose between the speed and steel, I’m leaning towards speed.