Vortex 4 flute "Tornado" Spiral. Are they worth the money?

I'm trying to get higher feedrates out of our cnc. We are mainly cutting hardwoods. I'm interested in the Vortex 4 flute "Tornado" downcut spiral bits. Is anyone using these? Are they worth the extra money? I am currently running 2 flute downspirals at 15000 rpm and 450 ipm. If I have my parts in a jig and I'm not worried about them moving, I've ran as high as 2000 ipm making cuts of 1/4" per pass. The vortex bits I mentioned are recommended to run at speeds no slower than 600 ipm. Just looking for some input here. What are you using? How fast are you cutting and how deep are you cutting?

I have used these bits to cut 3 sheets of 3/8" Plywood at once. I can run these bits a a very high Feed rate while still getting a perfect finish and They last a very long time. I am very happy with them and i personally think they are worth the cost