I love my Wavehopper. It's basically a more forgiving plastic wild water boat. I use it for whitewater attainment workouts once a week all year long; it makes fitness training a blast. It's the best combination of speed and durability of any boat made and it will last a lifetime. I used to have a glass boat, but I kept cracking it on rocks. The balance takes some getting used to, but once you get a few hours on the water it's very comfortable. It's much easier to balance and control then a real glass wild water boat (but not as fast either).
I tried a Pyranha Speeder, but it was not very maneuverable in whitewater. I have about six whitewater kayaks and my Wavehopper is probably the only one that I will never eventually get rid of. The only down side is that they are impossible to get a hold of in the U.S., you have to buy one in Europe and then ship it to the States or find one from the early 90's.