[amsat-bb] 70cm Helicoil Good/Bad expensive?

Hello all, whats the take on these antennas? I am sure someone on here has used them and they certainly look cool but how do they perform?

Dont you have to switch polerization on a cross polerized yagi?

I know there is not a perfect antenna, just wondering about the Helicoil...

Kevin KF7MYK