I hit the Big Bertha II driver on the range when I visited the Callaway Divine Nine. The one I hit was a regular flex with 10 degree loft. I can hit a Regular or a Stiff flex shaft in the driver and I didn’t have too much trouble hooking the ball with this shaft. It took about 15-20 swings before I got the head positioned properly; you hold the face closed at address.
Once I did, I was hitting it dead straight but really high – about the ball flight I see with my 5 iron. My current driver is a KZG PFT 300 with a 10.5 degree loft and I don’t hit it nearly as high. It was interesting to test it out. If I got the driver I’d probably look at it in an 8.5-9 degree loft.