I'm looking at them. Would like to hear from somebody who has used one.
I would invest in the Super Speed System.
I would use super speed as well but it is expensive for what it is. There are lots of speed training systems out there. You can also use a speed fan which is good as well and only $10 at Dicks all of them work to a degree.
At the end of the day you also need to do stretches and working out to fully realize your potential and to gain speed. No short cuts either you have to really work out a lot to have the desired effects and gain in speed.
I used the Super Speed system last winter and went from about 100 MPH to close to 115 in just under 3 months. I haven't kept up with it and am back to 105-110. Even if you don't use one of those systems, something that you can swing with weights will work. I can tell that it had a lot to do with the different "protocols" that I went through swinging them, not necessarily the Super Speed sticks themselves. I don't think it would work quite as well, but even buying one of the round weights to slide sown the shaft would probably help, as long as you swing it a dozen times a few days a week.