This topic about Birdieballs never really took off, but turned into a wiffleball topic.
I though I'd turn it back, having just gotten my hands on these Birdieballs myself!
I must say ... these weird looking "tubes" are absolutely brilliant. The design is pure genious.
From an aerodynamic perspective, the birdieball is high drag in the vertical rotation plane causing it to be very restricted in travelling distance.
In the lateral rotation plane, it is round like a normal ball, causing it to react very true to sidespin and thus slice, fade, draw and hook like a normal golf ball.
The result is a ball you can strike at with a full swing, that shows you a correct flight path profile, but still only travels a limited distance (35 meters from a 9-iron).
You can also analyze the backspin of the ball, simply by listening to the sound the "ball" makes in the air.
I've just spent a couple of hours whacking these balls over the fence and into my neighbours garden, where he - loudly giggling - would whack them back into mine.
You can even get a strike mat if you don't own a piece of lawn that you can tear apart - or live in a tarmac-clad area
Best golf-buy I've made for ages.